Health

Hidden Chemicals in Tea Bags That Harm Your Gut

5. Pesticide Residues Pesticide residues are a significant concern in tea production, as tea crops are often treated with chemical pesticides to control pests and increase… Alina Yasinskaya - August 14, 2025

Tea is the world’s most consumed beverage after water, with over 3.7 billion cups enjoyed daily according to the Statista Tea Market Report. While tea is cherished for its soothing effects, the digestive system—our gut—often faces the brunt of exposure to hidden chemicals present in tea bags. Many health-conscious consumers remain unaware of these risks, as the dangers are not always visible or listed. Recognizing and understanding the sources and effects of these hidden chemicals is a crucial step towards protecting gut health in today’s tea-loving world.

1. Epichlorohydrin

1. Epichlorohydrin
A tea bag rests beside a drawn chemical structure, highlighting the science behind tea’s benefits for gut health. | Generated by Google Gemini

Epichlorohydrin is a chemical compound commonly used as a wet-strength agent in the manufacturing of tea bags. Its primary role is to reinforce the paper fibers, ensuring the tea bag maintains its integrity and doesn’t fall apart when steeped in hot water. However, this convenience comes at a potential cost to gut health. According to the Agency for Toxic Substances and Disease Registry (ATSDR), epichlorohydrin can leach into your tea when exposed to hot water, and it has been linked to irritation of the digestive tract and possible carcinogenic effects in animal studies.

Long-term exposure to epichlorohydrin may disrupt the balance of gut flora and damage the intestinal lining, potentially leading to digestive discomfort and increased health risks. Spotting this chemical on packaging can be difficult, as it’s rarely listed directly. Instead, look for terms such as “wet-strengthened paper” or “reinforced paper” in the ingredients or manufacturing details. Brands that advertise unbleached or plastic-free tea bags are less likely to use epichlorohydrin. For more detailed information, visit the Environmental Working Group‘s report on tea bag materials.

2. Microplastics

2. Microplastics
A close-up under a microscope reveals tiny microplastics released from a synthetic tea bag’s delicate mesh fibers. | Generated by Google Gemini

Microplastics are tiny plastic particles that can be released from synthetic tea bags, particularly those made from nylon or polyethylene terephthalate (PET). When steeped in hot water, these tea bags may shed billions of microplastic and nanoplastic particles into the beverage, as demonstrated by a study published in Scientific Reports. These particles are not biodegradable and can accumulate in the digestive system, where they may disrupt the gut microbiome—the community of beneficial bacteria essential for digestion and immune health.

Research indicates that microplastics can cause gut inflammation, oxidative stress, and interference with nutrient absorption, potentially contributing to long-term gastrointestinal issues (National Institutes of Health). To avoid microplastic exposure, opt for tea brands that use paper, muslin, or other biodegradable materials for their tea bags. Look for products labeled as “plastic-free” or “compostable” and avoid those with shiny, silky, or mesh-like appearances. Loose-leaf tea brewed with a stainless steel or glass infuser is another effective alternative. For more insights, see the BBC’s report on microplastics in tea bags.

3. Chlorine Bleach

3. Chlorine Bleach
A white tea bag is submerged in a clear cup of chlorine bleach, capturing the moment a chemical reaction begins. | Generated by Google Gemini

Chlorine bleach is frequently used in the tea industry to whiten tea bags, giving them a clean and uniform appearance. However, this bleaching process can create potentially harmful byproducts, such as dioxins and chlorinated compounds. According to the U.S. Environmental Protection Agency (EPA), dioxins are highly toxic and can accumulate in the body over time, affecting multiple organ systems, including the digestive tract.

When tea bags treated with chlorine bleach are steeped in hot water, trace amounts of these byproducts may leach into your drink. Research published in the Environmental Health Perspectives journal highlights that dioxins can disrupt gut barrier function and harm the gut microbiome, leading to inflammation, digestive discomfort, and an increased risk of gastrointestinal diseases. To limit exposure, choose brands labeled “unbleached” or “chlorine-free.” Opting for loose-leaf tea or products certified organic also reduces the likelihood of encountering chlorine-bleached materials. For more details on chlorine use and its health impacts, visit the Environmental Working Group’s tea bag guide.

4. Glues and Adhesives

4. Glues and Adhesives
A close-up of tea bags being sealed with adhesive, highlighting concerns about potential gut irritation from the process. | Generated by Google Gemini

Many commercial tea bags are sealed using glues and adhesives rather than traditional stitching. These adhesives are often synthetic and can contain a variety of chemicals, including thermoplastics, polyvinyl chloride (PVC), and ethylene-vinyl acetate (EVA). When exposed to boiling water during steeping, some of these adhesive components may leach into the tea, potentially entering the digestive system. A report from The Guardian highlights concerns over adhesives, noting that their safety in hot consumables is not always well-regulated or fully disclosed.

Certain adhesive chemicals have been linked to digestive irritation, allergic reactions, and disruption of gut flora when ingested regularly. For sensitive individuals, repeated exposure might contribute to symptoms like bloating, cramps, and digestive discomfort. Since manufacturers rarely list adhesives on packaging, spotting their presence can be challenging. Look for brands that advertise “staple-free” or “string-and-tag” construction, or opt for loose-leaf teas that do not require sealing. For more comprehensive information on the chemicals used in tea bag adhesives and their potential health effects, consult the Food Packaging Forum’s analysis of tea bag materials.

5. Pesticide Residues

5. Pesticide Residues
A close-up view of fresh tea leaves sprinkled with pesticide, highlighting concerns about their impact on intestinal flora health. | Generated by Google Gemini

Pesticide residues are a significant concern in tea production, as tea crops are often treated with chemical pesticides to control pests and increase yield. These residues can persist not only on the tea leaves but also in the fibers of tea bag materials, potentially leaching into your beverage during steeping. According to a Consumer Reports investigation, some commercial teas have been found to contain measurable levels of pesticide residues.

When ingested, these chemicals can disrupt the delicate balance of intestinal flora, which play a crucial role in digestion and immune defense. Research from the National Institutes of Health (NIH) indicates that certain pesticides may reduce beneficial gut bacteria and promote inflammation, potentially leading to digestive issues and weakened gut health. To minimize risk, look for tea brands that carry certifications such as “USDA Organic,” “EU Organic,” or “Rainforest Alliance Certified,” as these labels indicate reduced or no synthetic pesticide use. For further guidance on safe tea purchasing, refer to the Environmental Working Group’s food safety resources.

6. Heavy Metals

6. Heavy Metals
A close-up of tea leaves steeping in hot water, illustrating how heavy metals may leach into the infusion. | Generated by Google Gemini

Heavy metals such as lead, aluminum, and cadmium have been detected in some tea bags, especially those made from low-quality materials or sourced from contaminated environments. When tea bags are steeped in hot water, these metals can leach into the beverage and be ingested. A study published in the Journal of Toxicology found that certain teas contain heavy metals at levels that may pose health risks if consumed regularly.

Exposure to heavy metals can lead to gut toxicity, interfering with the absorption of essential nutrients and causing inflammation of the intestinal lining. Over time, this may contribute to symptoms such as abdominal pain, cramping, and altered gut microbiota. Chronic exposure has also been linked to more severe health issues, including neurotoxicity and kidney damage. To reduce the risk, opt for teas from reputable brands that test for contaminants and avoid products packaged in metallic or unknown-origin tea bags. Additionally, avoid over-steeping tea, as prolonged contact with hot water can increase leaching. For more details on heavy metals in tea, see the ConsumerLab report on lead in tea.

7. Bisphenol A (BPA)

7. Bisphenol A (BPA)
Colorful plastic packaging surrounds everyday foods, while a magnified view reveals gut bacteria interacting with BPA molecules. | Generated by Google Gemini

Bisphenol A (BPA) is a synthetic compound frequently used in plastics, including some tea bag packaging and wrappers. BPA can migrate into hot beverages when tea bags are packaged in materials containing this chemical, especially when exposed to boiling water. According to the U.S. Food & Drug Administration (FDA), BPA is known for its endocrine-disrupting effects, meaning it can interfere with hormone function even at low exposure levels.

Recent research indicates that BPA exposure may also have significant impacts on gut health. A study published in Mucosal Immunology found that BPA disrupts the balance of gut bacteria, potentially increasing susceptibility to inflammation, digestive disorders, and metabolic issues. These alterations in the gut microbiome can weaken the gut’s immune defenses and disrupt the digestive process. To avoid BPA exposure, choose tea brands that use BPA-free labeling on their packaging or opt for loose-leaf teas stored in glass or paper containers. For additional information, refer to the Environmental Working Group’s guide to BPA in food packaging.

8. Dioxins

8. Dioxins
A stack of bright white bleached paper sits beside a graphic illustration of inflamed gut lining and a dioxin molecule. | Generated by Google Gemini

Dioxins are a group of highly toxic chemical compounds that can be produced as unintentional byproducts during the bleaching of paper, including that used for some tea bags. When bleached paper tea bags are steeped in hot water, trace amounts of dioxins may leach into your tea. The World Health Organization (WHO) warns that dioxins are persistent environmental pollutants that accumulate in the body and are linked to a variety of health risks.

Gut health is particularly vulnerable to dioxin exposure. Research published in Toxins (Basel) shows that dioxins can induce gut inflammation, disrupt the intestinal barrier, and alter the gut microbiome. These effects may lead to increased digestive discomfort, heightened inflammation, and a greater risk of intestinal disorders. To avoid dioxin exposure, select tea brands that use unbleached, chlorine-free tea bags or consider loose-leaf teas that forgo paper packaging entirely. For further reading on dioxins in food and safer alternatives, consult the Environmental Working Group’s overview of tea bag materials.

9. Polypropylene

9. Polypropylene
A close-up of a heat-sealed tea bag made from polypropylene, highlighting its role in safe, effective digestion. | Generated by Google Gemini

Polypropylene is a type of plastic commonly used as a heat-sealant in tea bags to help them retain their shape and prevent leaks during steeping. While it is considered stable under many conditions, research suggests that exposure to boiling water may cause small amounts of polypropylene or its breakdown products to migrate into the tea. According to a study published in Environmental Science & Technology, polypropylene microplastics have been detected in beverages prepared with plastic-sealed tea bags.

The ingestion of polypropylene particles raises concerns for digestive health. Although considered less toxic than some other plastics, there is evidence that microplastics—including polypropylene—can cause gut irritation and disrupt the balance of gut bacteria over time (NIH review). These disruptions can result in inflammation, impaired nutrient absorption, and altered digestive function. To minimize exposure, seek out tea brands that advertise “plastic-free” or “compostable” tea bags, or use loose-leaf tea with a metal or glass infuser. For more insights, read the BBC’s report on plastics in tea bags.

10. Acrylamide

10. Acrylamide
Researchers analyze gut lining samples under a microscope to study the effects of acrylamide formed during tea processing. | Generated by Google Gemini

Acrylamide is a chemical compound that can form in starchy foods during high-temperature processing, such as roasting or drying—processes sometimes used in tea production. While acrylamide is more commonly associated with foods like potato chips and coffee, studies have identified its presence in certain types of tea, especially black and roasted teas (National Institutes of Health). This compound is recognized as a potential gut irritant and has been classified as a probable human carcinogen by the National Cancer Institute.

Ingesting acrylamide may disrupt the gut lining and contribute to inflammation, which can impair digestion and increase the risk of gastrointestinal issues over time. Sensitive individuals may experience symptoms such as abdominal discomfort, bloating, or irregularity with chronic exposure. To minimize acrylamide intake, choose lightly processed teas such as green or white varieties, which generally undergo less intense heat treatment. Opting for reputable brands that test for contaminants and following proper brewing guidelines—such as avoiding over-steeping—can also help. For more in-depth information, review the FDA’s Q&A on acrylamide in food.

11. Formaldehyde

11. Formaldehyde
A close-up view of intestinal cells exposed to formaldehyde-based adhesive, highlighting their altered structure and cellular response. | Generated by Google Gemini

Formaldehyde is a volatile organic compound sometimes present in adhesives and resins used to seal tea bags. While its use in food contact materials is regulated, trace amounts can still migrate into hot beverages when tea bags are steeped, especially if lower-quality adhesives are employed. The National Cancer Institute classifies formaldehyde as a known human carcinogen, citing links to cancers of the respiratory and digestive tracts following chronic exposure.

Formaldehyde can have a damaging effect on gut health. Research published in Frontiers in Microbiology shows that even low-level exposure may injure gut epithelial cells, disrupt tight junctions, and promote inflammation. These disruptions can lead to leaky gut syndrome, increased gut permeability, and altered gut microbiota, all of which impair digestive and immune function. To reduce risk, select tea brands that avoid synthetic adhesives or advertise their use of “staple-free” or “chemical-free” sealing methods. Choosing loose-leaf teas prepared with stainless steel or glass infusers further minimizes exposure. For more details, see the FDA’s formaldehyde guidance.

12. Fluoride Residues

12. Fluoride Residues
A close-up of fresh tea leaves beside a glass of brewed tea highlights their natural fluoride content and digestive benefits. | Generated by Google Gemini

Fluoride is a naturally occurring mineral that can accumulate in tea leaves, particularly those harvested from older plants. Because tea plants absorb fluoride from the soil, certain teas—especially lower-cost, mature-leaf varieties—may contain higher levels of fluoride. According to the Centers for Disease Control and Prevention (CDC), excessive fluoride intake can pose health risks, including dental and skeletal fluorosis.

For the digestive system, overexposure to fluoride can irritate the stomach lining and disrupt gut health. Research published in the Journal of Toxicology and Environmental Health suggests that high levels of fluoride may alter the composition of gut bacteria, impair nutrient absorption, and contribute to gastrointestinal discomfort such as nausea, abdominal pain, or diarrhea. Individuals who consume large quantities of tea daily or those using fluoridated water for brewing are at greater risk of overexposure. To mitigate this, choose high-quality teas made from young leaves and limit daily consumption. Opting for organic brands that test for contaminants can also help. For further guidance, see the Environmental Working Group’s fluoride in tea report.

13. Polyvinyl Chloride (PVC)

13. Polyvinyl Chloride (PVC)
A flexible PVC sealing strip is shown coiled neatly, its smooth surface resembling the curves of an intestinal tract. | Generated by Google Gemini

Polyvinyl chloride (PVC) is a type of plastic occasionally used as a sealing material in some tea bags, though its use has become less common due to growing health concerns. PVC is not intended for food contact applications, but in rare cases, it may be present in lower-quality or unregulated tea products. When exposed to hot water, PVC can release breakdown products such as vinyl chloride monomer and phthalates, both of which have been identified as hazardous chemicals. The Centers for Disease Control and Prevention (CDC) notes that vinyl chloride is a known human carcinogen.

For the gut, ingestion of PVC breakdown products poses significant risks. Research in Environmental Health Perspectives has shown that these compounds can damage the intestinal lining, disrupt gut flora, and trigger inflammation. Chronic exposure may contribute to digestive issues such as abdominal pain, bloating, and even increased cancer risk. To avoid PVC exposure, favor tea brands that explicitly state their use of food-grade, plastic-free, or biodegradable materials. Opting for loose-leaf tea and glass or stainless steel infusers provides an added layer of safety. For more on PVC in food packaging, refer to the Food Packaging Forum’s resource on PVC.

14. Colorants

14. Colorants
A decorative tea bag with vibrant colorants sits on a saucer, featuring a clear allergy warning on its tag. | Generated by Google Gemini

Synthetic colorants are sometimes added to decorative tea bags or their strings and tags to enhance visual appeal and differentiate flavors or brands. These artificial dyes, such as FD&C colors, are not always intended for ingestion but may leach into tea during steeping. The U.S. Food & Drug Administration (FDA) regulates the use of food colorants, but some dyes used in packaging or decorative elements may not be food-grade.

When synthetic colorants are absorbed through the gut, they can trigger a range of adverse effects, especially in sensitive individuals. According to the National Institutes of Health, certain artificial dyes have been linked to allergic reactions, hyperactivity, and even changes in gut microbiota. Allergenic responses may include rashes, itching, or gastrointestinal symptoms such as cramps and diarrhea. To avoid unnecessary exposure, select teas with plain, uncolored bags and strings, or opt for loose-leaf teas with minimal packaging. For a deeper look at colorants in food and their health implications, visit the Center for Science in the Public Interest’s Food Dyes resource.

15. Preservatives

15. Preservatives
A close-up of a tea bag steeping in a glass mug, highlighting its preservative content and impact on gut bacteria. | Generated by Google Gemini

Preservatives are sometimes added to tea bags or their packaging to extend shelf life, prevent mold growth, and maintain freshness during long storage or shipping periods. Common preservatives include sulfur dioxide, sodium benzoate, and potassium sorbate. While these chemicals are generally recognized as safe in small amounts by regulatory agencies like the U.S. Food & Drug Administration (FDA), they can disrupt the natural balance of gut bacteria, especially with frequent consumption.

Research published in Frontiers in Microbiology shows that certain preservatives may inhibit the growth of beneficial gut microbes while allowing harmful bacteria to flourish. This imbalance, known as dysbiosis, can lead to digestive discomfort, reduced immune function, and increased susceptibility to gastrointestinal disorders. Sensitive individuals may also experience allergic reactions or intolerance symptoms such as nausea, abdominal pain, or diarrhea. To avoid unnecessary preservatives, look for tea brands that emphasize minimal processing, organic certification, or “no additives” on their labels. Choosing loose-leaf teas or those with transparent ingredient lists is also a good strategy. For more information, see the Environmental Working Group’s guide to food preservatives.

16. Residual Solvents

16. Residual Solvents
A lab technician carefully examines a solvent mixture in a manufacturing facility focused on ensuring digestive safety standards. | Generated by Google Gemini

Residual solvents are chemicals sometimes used during the manufacturing and processing of tea bag materials, including the extraction of plant fibers or the formation of synthetic components. Common solvents include ethanol, acetone, and dichloromethane. Although most solvents are removed before the final product is assembled, trace amounts can remain and may leach into tea during steeping. According to the U.S. Food & Drug Administration (FDA), exposure to residual solvents should be minimized, as some have known toxicological effects.

Ingestion of residual solvents can pose digestive risks, including irritation of the stomach and intestines, disruption of gut epithelial cells, and alteration of the natural gut microbiome. Research published in Environmental Science and Pollution Research indicates that long-term exposure to certain solvents, even at low levels, can contribute to gastrointestinal discomfort and increase the risk of chronic gut issues. To reduce risk, opt for teas from reputable brands with transparent sourcing and manufacturing practices. Look for certifications like “solvent-free processing” or “organic,” which typically involve stricter controls. For further reading, visit the Food Packaging Forum’s overview of solvents in food materials.

17. Perfluorinated Compounds (PFCs)

17. Perfluorinated Compounds (PFCs)
A close-up of a water-resistant tea bag coated with PFC, highlighting its impact on gut permeability. | Generated by Google Gemini

Perfluorinated compounds (PFCs) are synthetic chemicals sometimes used to make tea bags water-resistant, preventing them from breaking apart during steeping. These compounds are highly persistent in the environment and can bioaccumulate in the human body. The U.S. Environmental Protection Agency (EPA) has raised concerns about the health effects of PFCs, noting their long half-lives and potential to accumulate through repeated exposure.

Research has shown that PFCs can negatively affect gut health by increasing intestinal permeability, often referred to as “leaky gut.” A study published in Environmental Health Perspectives found that PFC exposure may disrupt tight junctions between gut epithelial cells, allowing toxins and pathogens to enter the bloodstream more easily. This can lead to chronic inflammation, digestive discomfort, and a heightened risk of gut-related diseases. To avoid PFCs, look for tea bags labeled as “uncoated,” “plastic-free,” or “compostable.” Opting for loose-leaf teas and brands with transparent, chemical-free manufacturing processes also helps reduce exposure. For more on PFCs in food packaging, visit the Environmental Working Group’s resource on PFCs.

18. Phthalates

18. Phthalates
Colorful plastic containers surround a magnified illustration of gut bacteria, highlighting the impact of phthalates on gut flora balance. | Generated by Google Gemini

Phthalates are a group of chemicals used to make plastics more flexible and durable, and they can be present in some plastic tea bag components, such as mesh bags, seals, or packaging. These compounds can leach into tea when exposed to hot water during steeping. The Centers for Disease Control and Prevention (CDC) notes that phthalates are well-known endocrine disruptors, capable of interfering with hormone regulation even at low levels of exposure.

Beyond their hormone-disrupting properties, phthalates can also negatively impact gut health. Research published in Frontiers in Public Health indicates that phthalate exposure may disrupt the gut microbiome, reduce populations of beneficial bacteria, and promote inflammation within the digestive tract. This imbalance in gut flora can contribute to digestive discomfort, increased susceptibility to gastrointestinal disorders, and impaired immune function. To minimize phthalate exposure, select tea brands that use “phthalate-free” or “plastic-free” materials and opt for loose-leaf teas brewed with non-plastic infusers. For more information, see the Environmental Working Group’s phthalate research resource.

19. Mineral Oils

19. Mineral Oils
A close-up of machinery parts coated in mineral oil, highlighting a warning label about potential gut irritation risks. | Generated by Google Gemini

Mineral oil hydrocarbons, including mineral oil saturated hydrocarbons (MOSH) and mineral oil aromatic hydrocarbons (MOAH), are often used as lubricants in food processing machinery, including those that manufacture tea bags. During production, these substances can inadvertently transfer onto tea bag materials, raising concerns about contamination and residue risk. The European Food Safety Authority (EFSA) has identified mineral oil hydrocarbons as common food contaminants, with potential health implications.

When ingested, mineral oil residues can irritate the gut lining and disrupt normal digestive processes. Research in Current Opinion in Food Science suggests that chronic exposure to MOSH and MOAH may lead to inflammation, impaired nutrient absorption, and the potential accumulation of hydrocarbons in body tissues. Individuals with sensitive digestive systems may experience symptoms such as bloating, abdominal pain, or altered gut motility. To reduce the risk of exposure, choose teas from manufacturers that adhere to strict quality controls and food safety certifications. Look for brands that perform regular contaminant testing and offer transparency in their processing methods. For more on mineral oil risks, see the Food Packaging Forum’s mineral oil hydrocarbons resource.

20. Synthetic Fragrances

20. Synthetic Fragrances
A person holds a fragrant aromatic tea bag near their nose, triggering an unexpected allergic response with a sneeze. | Generated by Google Gemini

Synthetic fragrances are sometimes added to tea bags to enhance aroma and create a more appealing sensory experience. These artificial scents may be present in both the tea leaves and the packaging, particularly in flavored or specialty teas. Commonly used fragrance chemicals include artificial esters, aldehydes, and other volatile organic compounds. According to the U.S. Food & Drug Administration (FDA), synthetic fragrances can be composed of dozens of individual chemicals, some of which are not intended for ingestion.

When hot water is added, synthetic fragrances can dissolve and be absorbed in the digestive tract. Research published in Frontiers in Pharmacology shows that some fragrance ingredients may disrupt gut epithelial integrity, trigger immune responses, and alter gut microbiota composition. Individuals who are sensitive or allergic to certain fragrance compounds may experience gastrointestinal symptoms such as nausea, cramps, or diarrhea, as well as systemic allergic reactions. To avoid synthetic fragrances, look for teas labeled as “unscented,” “fragrance-free,” or “naturally flavored,” and favor brands with transparent ingredient lists. For more on fragrance chemicals and health, see the Environmental Working Group’s fragrance database.

21. Silicone Compounds

21. Silicone Compounds
A stream of hot water pours over a silicone seal, demonstrating its durability and watertight protection. | Generated by Google Gemini

Silicone compounds are sometimes used in specialty tea bags, particularly as seals or flexible components designed to enhance durability and prevent leaks. While silicone is generally considered more stable and inert than many plastics, it can still release trace amounts of siloxanes or other breakdown products when exposed to boiling water. The U.S. Food & Drug Administration (FDA) permits the use of food-grade silicone, but long-term effects of ingestion are still being studied.

When silicone compounds migrate from tea bags into hot beverages, they may be absorbed in the digestive tract. Research published in Toxicology and Applied Pharmacology indicates that some siloxanes could disrupt gut epithelial cells and potentially alter the gut microbiome, though the risks are considered lower than with many synthetic plastics. Sensitive individuals may experience mild gastrointestinal irritation or discomfort from repeated exposure. To minimize potential risks, opt for tea brands that disclose their use of packaging materials and avoid those with silicone seals when possible. For a broader discussion, see the Food Packaging Forum’s analysis of silicone in food packaging.

22. Ethylene Oxide

22. Ethylene Oxide
A technician carefully prepares medical instruments for ethylene oxide sterilization, ensuring safe use in gastrointestinal tract procedures. | Generated by Google Gemini

Ethylene oxide is a chemical sterilant sometimes used to disinfect tea bag materials and packaging, especially in large-scale production to eliminate bacteria, fungi, and pests. While this process helps ensure product safety, traces of ethylene oxide or its byproducts, such as 2-chloroethanol, may remain on the final product. The U.S. Food & Drug Administration (FDA) regulates permissible residue levels, but concerns about cumulative exposure persist.

Ethylene oxide is classified as a human carcinogen by the National Cancer Institute, and animal studies suggest it can irritate the gastrointestinal tract, leading to symptoms such as nausea, abdominal pain, and diarrhea. Chronic ingestion, even at low levels, may disrupt gut epithelial cells and alter the gut microbiome, increasing the likelihood of inflammation and impaired digestion. To reduce risk, choose tea brands that use alternative sterilization methods such as steam or irradiation, and check for certifications like “ethylene oxide-free.” For further information on ethylene oxide residues and food safety, visit the European Food Safety Authority’s Q&A on ethylene oxide in food.

23. Sulfur Dioxide

23. Sulfur Dioxide
Fresh tea leaves are carefully examined under a microscope to detect sensitivity to sulfur dioxide exposure. | Generated by Google Gemini

Sulfur dioxide is a common preservative used in the food industry to prevent spoilage and maintain color, and it is sometimes applied to dried tea leaves during processing. This chemical helps inhibit the growth of mold and bacteria, extending the shelf life of tea products. According to the U.S. Food & Drug Administration (FDA), sulfur dioxide is generally recognized as safe when used within regulated limits, but it can pose problems for sensitive individuals.

When sulfur dioxide-treated tea is brewed, residues may dissolve into the beverage. Some people—especially those with asthma or sulfite sensitivity—may experience adverse digestive reactions, including abdominal pain, cramps, diarrhea, or bloating. Research published in World Journal of Gastroenterology indicates that sulfur dioxide can irritate the gastrointestinal tract and disrupt gut microbiota in susceptible individuals. To minimize exposure, look for teas labeled “preservative-free” or “sulfite-free,” and choose organic brands, which typically avoid synthetic preservatives. Regulatory agencies like the FDA and European Food Safety Authority (EFSA) set strict limits on allowable sulfur dioxide levels, but reading ingredient lists remains crucial for sensitive consumers.

24. Lead

24. Lead
An illustration shows lead particles entering the digestive system, highlighting the process of intestinal absorption and contamination risks. | Generated by Google Gemini

Lead contamination in tea can occur due to uptake from polluted soils, water sources, or during manufacturing processes, particularly in regions where environmental controls are lacking. Lead can accumulate in tea leaves and, consequently, in tea bags, posing a risk when the tea is brewed and consumed. The World Health Organization (WHO) highlights that there is no safe level of lead exposure, especially for vulnerable populations such as children and pregnant women.

When ingested, lead can accumulate in the gut and be absorbed into the bloodstream, leading to both acute and chronic health problems. Research published in Frontiers in Pharmacology reveals that lead exposure can damage the gut lining, disrupt the balance of gut microbiota, impair nutrient absorption, and promote inflammation. Symptoms of lead toxicity include abdominal pain, nausea, constipation, and long-term cognitive and developmental issues. To reduce risk, choose teas from reputable brands that conduct regular heavy metal testing and source their products from regions with strict environmental standards. For more information on lead in tea, visit the ConsumerLab report on lead contamination.

25. Aluminum

25. Aluminum
An aluminum staple embedded in inflamed gut tissue highlights the risks of foreign objects causing internal irritation. | Generated by Google Gemini

Aluminum is sometimes used in the staples that hold tea bags together or as a component in the lining of certain types of tea bag packaging. When tea bags with aluminum staples are steeped in hot water, there is a potential risk of aluminum leaching into the beverage, especially if the staple is exposed or if the tea bag material degrades. The Agency for Toxic Substances and Disease Registry (ATSDR) notes that while small amounts of aluminum are typically excreted, high or chronic exposure can be problematic.

Ingested aluminum can reach the gastrointestinal tract and, at elevated levels, may contribute to gut inflammation and disrupt the gut barrier. Research published in Environmental Sciences Europe suggests that excessive aluminum intake can alter gut microbiota, impair nutrient absorption, and provoke inflammatory responses in sensitive individuals. Symptoms may include abdominal pain, nausea, or changes in bowel habits. To avoid unnecessary exposure, choose tea brands that use staple-free, biodegradable, or string-and-tag tea bag designs. For more insights on aluminum in food and beverage products, refer to the European Food Safety Authority’s scientific opinion on aluminum in food.

26. Styrene

26. Styrene
A close-up of white styrene plastic mesh, highlighting its potential impact on digestive health and food safety concerns. | Generated by Google Gemini

Styrene is a chemical compound used in the production of polystyrene plastics, which may be found in some mesh tea bags designed for a more premium or visually appealing presentation. When hot water comes into contact with polystyrene-based mesh, styrene monomers can migrate into the tea. The National Cancer Institute classifies styrene as a possible human carcinogen, raising concerns about its presence in food and beverage packaging.

Ingesting styrene via tea can have adverse effects on digestive health. Research published in Toxics indicates that styrene may irritate the gut lining, disrupt epithelial cell function, and alter the gut microbiome, potentially leading to inflammation and digestive discomfort. Chronic exposure, even at low levels, has been linked to gastrointestinal symptoms such as nausea, abdominal pain, and changes in bowel habits. To minimize the risk of styrene exposure, select teas packaged in paper, muslin, or other natural fibers, and avoid tea bags with a shiny, mesh-like appearance. For a detailed overview of styrene risks, visit the FDA’s styrene Q&A.

27. Carbon Disulfide

27. Carbon Disulfide
Workers in protective gear monitor vats of rayon fibers as carbon disulfide fumes swirl, highlighting the process’s hidden toxicity. | Generated by Google Gemini

Carbon disulfide is a chemical solvent used in the production of rayon, a semi-synthetic fiber sometimes found in tea bag materials. Rayon is valued for its smooth texture and strength, but its manufacturing process can leave trace residues of carbon disulfide in the final product. According to the Centers for Disease Control and Prevention (CDC), carbon disulfide exposure is associated with a range of health concerns, particularly when ingested or inhaled over time.

If carbon disulfide residues remain in rayon-based tea bags, they can leach into hot water during steeping and be consumed with the tea. Research published in Environmental Science and Pollution Research suggests that carbon disulfide can be toxic to the digestive system, causing irritation of the gut lining, altering gut flora, and potentially leading to symptoms such as abdominal pain, nausea, or diarrhea. Chronic exposure has been linked to more serious health risks, including neurotoxicity. To avoid carbon disulfide residues, opt for tea bags made from unbleached paper, cotton, or other natural fibers, and consider loose-leaf tea as a safer alternative. For more on rayon and its health effects, visit the Healthy Building Network’s rayon fact sheet.

28. Nitrates and Nitrites

28. Nitrates and Nitrites
A farmer spreads nitrate-rich fertilizer across lush green fields, while an inset diagram illustrates gut conversion in livestock. | Generated by Google Gemini

Nitrates and nitrites are chemical compounds frequently used in agricultural fertilizers to enhance crop yield, including tea plants. These compounds can accumulate in tea leaves and, subsequently, in tea bags. When tea is brewed and consumed, nitrates and nitrites can enter the digestive system. According to the World Health Organization (WHO), nitrates themselves are relatively inert, but can be converted by gut bacteria into nitrites, which may then form harmful nitrosamines—compounds linked to an increased risk of cancer.

Research published in Nutrients indicates that high intake of nitrates and nitrites may disrupt the gut microbiome, impair enzyme function, and increase the risk of gastrointestinal disorders, particularly in populations with low stomach acid or altered gut flora. Some individuals may experience symptoms such as nausea, abdominal cramps, or diarrhea with excessive exposure. To limit ingestion, choose organic teas or those certified as “pesticide- and fertilizer-free,” which are less likely to contain elevated nitrate or nitrite levels. For more information on the risks of nitrates and nitrites in foods and beverages, see the FDA’s Q&A on nitrites and nitrates.

29. Triclosan

29. Triclosan
A scientist examines bacterial cultures in petri dishes, highlighting triclosan’s antimicrobial effects and impact on the microbiome. | Generated by Google Gemini

Triclosan is an antimicrobial agent sometimes incorporated into packaging materials to inhibit bacterial growth and extend shelf life, though its use in tea bag packaging is rare and declining due to regulatory scrutiny. Despite this, trace amounts could still be present in imported or non-certified products. The U.S. Food & Drug Administration (FDA) has banned triclosan from certain consumer goods but does not regulate its use in all packaging materials.

When present, triclosan can leach into hot beverages during steeping and enter the digestive tract. Research published in Nature Communications demonstrates that triclosan exposure disrupts the gut microbiome, reducing populations of beneficial bacteria and promoting the growth of resistant or harmful strains. These changes can impair digestion, weaken immune function, and increase susceptibility to infections and inflammatory diseases. To avoid triclosan exposure, select teas with clear “antimicrobial-free” or “triclosan-free” labeling and favor brands with transparent sourcing and packaging practices. For more on triclosan’s health effects and regulatory status, see the Environmental Working Group’s triclosan resource.

30. Polyethylene

30. Polyethylene
A close-up view of a polyethylene pouch sealed with heat, designed to maintain gut integrity during storage and transport. | Generated by Google Gemini

Polyethylene is a widely used plastic polymer, often employed as a heat-sealable layer in some tea bags to help them retain their structure during steeping. While polyethylene is generally considered relatively stable, exposure to boiling water can cause minor degradation or the release of microplastic particles and chemical additives into the tea. According to the U.S. Food & Drug Administration (FDA), food-grade polyethylene is deemed safe for many uses, but recent studies have raised concerns about plastic migration from packaging into hot consumables.

Ingestion of microplastics or polyethylene-derived compounds may negatively affect gut integrity. Research published in Frontiers in Microbiology indicates that microplastic exposure can disrupt gut epithelial cells, alter the gut microbiota, and trigger inflammation. Over time, these changes may impair nutrient absorption and weaken the gut barrier, increasing vulnerability to digestive disorders. To minimize polyethylene exposure, opt for teas marketed as “plastic-free” or “compostable,” or choose loose-leaf varieties brewed with metal or glass infusers. For further insights on plastics in food and beverage packaging, explore the Food Packaging Forum’s polyethylene resource.

31. Benzene

31. Benzene
A detailed illustration shows benzene molecules being absorbed through the digestive tract, highlighting the risk of chemical contamination. | Generated by Google Gemini

Benzene is a volatile organic compound that can become a contaminant in tea bag materials through several pathways, including exposure during the manufacturing of synthetic fibers, adhesives, or inks used in packaging. Although not intentionally added to tea bags, benzene can be present as a trace impurity, particularly in products made from plastics or processed with certain solvents. The National Cancer Institute and the U.S. Environmental Protection Agency (EPA) classify benzene as a known human carcinogen, linked to leukemia and other blood disorders.

When tea bags containing benzene residues are steeped in hot water, small amounts of this chemical may migrate into the beverage and be absorbed through the digestive tract. Chronic benzene exposure can damage gut epithelial cells, impair immune function, and disrupt the gut microbiome, as noted in a review published in Environmental Health Perspectives. Symptoms of benzene toxicity include abdominal discomfort, nausea, and long-term risks of cancer and hematological disorders. To reduce the risk, choose teas from reputable brands with transparent sourcing and minimal synthetic packaging. For more on benzene in consumer products, see the Environmental Working Group’s benzene overview.

32. Residual Detergents

32. Residual Detergents
A laboratory technician uses detergent in a fiber processing experiment, highlighting the connection between dietary fiber and GI upset. | Generated by Google Gemini

Residual detergents are sometimes left behind on tea bag fibers as a result of industrial cleaning and processing steps used to prepare plant or synthetic materials. Detergents such as sodium lauryl sulfate and other surfactants help remove natural impurities, oils, and contaminants during manufacturing. However, inadequate rinsing or quality control can leave trace amounts of these chemicals on the finished tea bag product. The Agency for Toxic Substances and Disease Registry (ATSDR) notes that certain detergents can cause irritation if ingested in significant quantities.

When tea bags with residual detergent are steeped in hot water, these chemicals may dissolve into the beverage and enter the digestive tract. Even in small amounts, ingestion of detergents can disrupt the gut lining, alter the natural mucus barrier, and provoke gastrointestinal upset, such as nausea, cramping, or diarrhea. Research published in Frontiers in Microbiology indicates that some surfactants may also disturb the gut microbiome, reducing populations of beneficial bacteria. To minimize risk, select tea brands with strict manufacturing protocols and certifications for food safety. For more on detergents in food contact materials, refer to the Food Packaging Forum’s analysis.

33. Nonylphenol Ethoxylates

33. Nonylphenol Ethoxylates
A laboratory flask filled with nonylphenol ethoxylate surfactant sits beside molecular diagrams highlighting its endocrine-disrupting properties. | Generated by Google Gemini

Nonylphenol ethoxylates (NPEs) are synthetic surfactants sometimes used in the processing and manufacturing of tea bag fibers and packaging materials. These compounds aid in cleaning, emulsifying, and improving the texture of plant and synthetic fibers. However, NPEs are known for their environmental persistence and resistance to biodegradation, leading to their classification as concerning contaminants by the U.S. Environmental Protection Agency (EPA).

When residual NPEs remain on tea bag materials, they can leach into tea during steeping and be ingested. Research published in Environmental Health Perspectives reveals that NPEs act as endocrine disruptors, interfering with hormone signaling and reproductive function in both animals and humans. Within the digestive system, NPEs may alter gut endocrine function, disrupt the balance of microbiota, and impair the gut’s natural defense mechanisms. These changes can contribute to digestive discomfort, immune dysregulation, and increased risk of metabolic disorders. To avoid exposure, select teas produced by brands that adhere to strict environmental and processing standards and clearly label their products as “NPE-free.” For further reading, visit the Environmental Working Group’s surfactant resource.

34. Toluene

34. Toluene
A printing press in action releases fumes, illustrating the potential impact of toluene exposure on gut health. | Generated by Google Gemini

Toluene is an aromatic hydrocarbon solvent commonly used in inks and adhesives for printing tea bag tags and packaging. During the manufacturing process, some toluene residue may remain on printed surfaces, and it can migrate into tea when the tag or packaging comes into contact with hot water. The Centers for Disease Control and Prevention (CDC) identifies toluene as a volatile organic compound with potential health risks upon ingestion or inhalation.

When ingested, even in trace amounts, toluene can be absorbed in the digestive tract, where it may cause irritation, disrupt gut epithelial cells, and alter the gut microbiome. Research in Environmental Science and Pollution Research indicates that toluene exposure is associated with gastrointestinal symptoms such as nausea, abdominal pain, and changes in bowel habits. Chronic or repeated exposure may also contribute to systemic toxicity, affecting liver and nervous system function. To reduce the risk of toluene ingestion, choose teas with unprinted tags or brands that utilize food-grade, low-residue inks and adhesives. For more on toluene in food packaging, visit the Food Packaging Forum’s overview of toluene.

35. Cadmium

35. Cadmium
Bright green plants thrive in rich brown soil while illustrating the bioaccumulation of cadmium in their roots and leaves. | Generated by Google Gemini

Cadmium is a toxic heavy metal that can be absorbed by tea plants from contaminated soils, often due to industrial pollution, use of phosphate fertilizers, or proximity to mining activities. Once taken up by the plant, cadmium can accumulate in tea leaves and persist through processing, eventually making its way into tea bags. The World Health Organization (WHO) warns that cadmium is highly persistent in the environment and can bioaccumulate in human tissues over time.

When tea containing cadmium is consumed, the metal is absorbed in the digestive tract and may build up in the body, particularly in the liver and kidneys. Research published in Frontiers in Pharmacology demonstrates that cadmium exposure can damage the intestinal lining, disrupt the gut microbiome, and impair nutrient absorption. Chronic ingestion is associated with gastrointestinal symptoms such as abdominal pain, nausea, and vomiting, as well as long-term risks including kidney dysfunction and increased cancer risk. To minimize cadmium intake, select teas from reputable sources with rigorous heavy metal testing and certified organic practices. For more information, consult the ConsumerLab guide to heavy metals in tea.

36. Polycyclic Aromatic Hydrocarbons (PAHs)

36. Polycyclic Aromatic Hydrocarbons (PAHs)
A microscopic view reveals polycyclic aromatic hydrocarbons accumulating along the gut lining during a critical drying process. | Generated by Google Gemini

Polycyclic aromatic hydrocarbons (PAHs) are a group of chemical compounds formed during the incomplete combustion of organic material. In tea production, PAHs can be generated during the drying and roasting processes, particularly when tea leaves are exposed to smoke or direct flame. These compounds may remain in the final product and leach into tea when brewed. The European Food Safety Authority (EFSA) and National Cancer Institute recognize certain PAHs as potent carcinogens.

Once ingested, PAHs can be absorbed through the gut lining and have been shown to cause cellular damage, promote inflammation, and increase the risk of gastrointestinal cancers. Research published in Frontiers in Genetics indicates that PAH exposure may also disrupt the gut barrier, impairing its protective function and altering the composition of the gut microbiota. To reduce exposure, choose teas from brands that use controlled, smoke-free drying techniques and regularly test for contaminants. For more on PAHs in food and beverage products, see the Food Packaging Forum’s PAH resource.

37. Ammonium Compounds

37. Ammonium Compounds
A bottle of industrial bleaching agent labeled “ammonium” sits beside warning signs about potential digestive irritation. | Generated by Google Gemini

Ammonium compounds, such as ammonium persulfate or ammonium chloride, are sometimes used as bleaching agents in the processing of tea bag paper to achieve a white, uniform appearance. While these chemicals effectively break down pigments and impurities, residues may remain in the finished tea bag material. The Centers for Disease Control and Prevention (CDC) notes that certain ammonium compounds can be irritating to mucous membranes and sensitive tissues.

When tea bags treated with ammonium-based agents are steeped in hot water, trace residues can dissolve and be ingested. Research in Frontiers in Pharmacology suggests that ingestion of ammonium compounds may irritate the digestive tract, leading to symptoms such as nausea, abdominal discomfort, and in some cases, disturbances in gut microbiota composition. Sensitive individuals may experience heightened gastrointestinal symptoms or allergic reactions. To minimize exposure, choose teas labeled as “unbleached” or “chlorine- and chemical-free,” and favor brands that emphasize natural processing methods. For additional information on ammonium compounds in food packaging and their effects, consult the Food Packaging Forum’s ammonium compounds resource.

38. Ethyl Acetate

38. Ethyl Acetate
Laboratory glassware filled with ethyl acetate stands beside coffee beans, illustrating the science behind decaffeination and metabolism. | Generated by Google Gemini

Ethyl acetate is a solvent commonly used in the decaffeination process for tea leaves, prized for its efficiency in removing caffeine while preserving flavor. Although considered a “natural” solvent since it can be derived from fruit, ethyl acetate used in industrial decaffeination is often synthetic. Trace amounts of this solvent may remain in decaffeinated tea leaves and subsequently end up in tea bags. The U.S. Food & Drug Administration (FDA) permits its use within regulated limits, but cumulative exposure is a concern for sensitive individuals.

When tea bags containing ethyl acetate residues are steeped, the solvent can dissolve into the brewed tea and be ingested. Research published in Toxicology Reports indicates that although ethyl acetate is rapidly metabolized in the liver, chronic or excessive intake may disrupt gut enzyme activity, alter gut microbiota, and cause mild gastrointestinal irritation, including nausea or stomach discomfort. To avoid ethyl acetate, look for teas labeled as “CO2 decaffeinated” or “water processed,” which use non-solvent methods. For more details, visit the Center for Science in the Public Interest’s ethyl acetate overview.

39. Xylene

39. Xylene
A laboratory technician carefully examines bottles of xylene-based ink, highlighting concerns over chemical toxicity and safe handling. | Generated by Google Gemini

Xylene is an aromatic hydrocarbon solvent commonly used in the production of printing inks for tea bag tags, labels, and some packaging materials. During the manufacturing process, trace amounts of xylene can remain in the ink and potentially migrate to the tea bag tag. If the tag comes into contact with hot water during steeping, small quantities of xylene may leach into the beverage. The Centers for Disease Control and Prevention (CDC) identifies xylene as a hazardous chemical with both short- and long-term health concerns.

Once ingested, xylene can be absorbed through the gut lining, where it may disrupt epithelial cell integrity and alter the gut microbiome. Research published in Environmental Science and Pollution Research shows that xylene exposure can cause symptoms such as nausea, abdominal pain, and diarrhea, while chronic exposure is linked to systemic toxicity affecting the liver and nervous system. To reduce the risk of xylene ingestion, choose teas with unprinted or minimally printed tags, or those using food-grade, low-residue inks. For more information on xylene in food packaging, see the Food Packaging Forum’s xylene resource.

40. Benzyl Alcohol

40. Benzyl Alcohol
A close-up of benzyl alcohol in a glass vial, highlighting its role as a preservative and potential for sensitivity. | Generated by Google Gemini

Benzyl alcohol is an aromatic alcohol occasionally used as a preservative or solvent in food and beverage products, including some flavored or specialty teas. It can also be present as a minor component in the inks and adhesives used for tea bag tags and packaging. The U.S. Food & Drug Administration (FDA) allows the use of benzyl alcohol as a food additive within regulated limits, but certain individuals may experience sensitivity to this compound.

When tea bags containing benzyl alcohol are steeped, the compound may dissolve into the tea and be ingested. In the digestive tract, benzyl alcohol is typically metabolized to benzoic acid and then excreted, but for sensitive individuals, this process can trigger symptoms such as nausea, abdominal pain, or allergic reactions. Research in Toxicological Research notes that large or repeated exposures might lead to gut irritation and even mild toxicity, especially in those with metabolic disorders or allergies. To avoid benzyl alcohol, choose teas marked as “preservative-free,” with minimal artificial flavors, and opt for brands with transparent ingredient disclosure. For more on food additives and sensitivities, visit the Environmental Working Group’s food additives guide.

41. Synthetic Resins

41. Synthetic Resins
A close-up view of a resin-coated mesh illustrates its role in reinforcing and protecting the delicate gut barrier. | Generated by Google Gemini

Synthetic resins, such as polyester and polyamide, are often used to create the fine mesh in premium or pyramid-shaped tea bags. These resins are valued for their strength, flexibility, and ability to withstand high temperatures. However, when exposed to boiling water, small amounts of resin breakdown products or microplastics may leach into the tea. The Food Packaging Forum notes that synthetic polymers and resins can release oligomers and additives, some of which may migrate into hot beverages.

Once ingested, these breakdown products and microplastics can reach the gut, where they have the potential to disrupt the gut barrier and alter the composition of the microbiome. Research published in Frontiers in Microbiology indicates that chronic exposure to microplastics and resin fragments can provoke gut inflammation, impair nutrient absorption, and weaken the integrity of the intestinal lining. Sensitive individuals may experience symptoms such as bloating, discomfort, or changes in bowel habits. To avoid synthetic resins, look for teas in paper or cotton bags or opt for loose-leaf tea with non-plastic infusers. For more on synthetic resins in food packaging, see the Food Packaging Forum’s analysis of resin migration.

42. Traces of Glyphosate

42. Traces of Glyphosate
A scientist examines gut microbiome samples in petri dishes, exploring the effects of glyphosate herbicide exposure. | Generated by Google Gemini

Glyphosate is a widely used herbicide in conventional agriculture, including in tea cultivation. Residues of glyphosate can remain on harvested tea leaves and end up in tea bags, particularly if the crops are not organically grown. The Environmental Working Group (EWG) has raised concerns about glyphosate persistence in various foods and beverages, including tea.

When consumed, glyphosate residues can influence the gut microbiome. Research published in Environmental Health Perspectives indicates that glyphosate may inhibit the growth of beneficial gut bacteria while allowing pathogenic strains to flourish, potentially leading to gut dysbiosis, inflammation, and impaired digestion. Some studies also suggest a possible link between glyphosate exposure and increased risk of gastrointestinal disorders. To minimize exposure, look for tea brands that are “USDA Organic,” “EU Organic,” or “Glyphosate Residue Free” certified, as these certifications prohibit or strictly limit the use of synthetic herbicides. For more guidance on avoiding glyphosate in tea and other foods, consult the EWG’s food additive guide and verify certifications on packaging.

43. Ethanol Residues

43. Ethanol Residues
A glass flask filled with golden ethanol gently extracts vibrant flavors from botanicals, mimicking the process of natural digestion. | Generated by Google Gemini

Ethanol is commonly used in the extraction of natural flavors and essential oils that are added to some specialty or flavored teas. While most of the solvent is removed during production, trace ethanol residues may remain in the tea leaves or tea bag material. The U.S. Food & Drug Administration (FDA) deems food-grade ethanol safe in low quantities, but cumulative exposure and sensitivities remain concerns for certain individuals.

When tea bags containing residual ethanol are steeped, small amounts can dissolve into the beverage and be ingested. Ethanol is rapidly absorbed in the digestive tract and metabolized by the liver, but for sensitive individuals or those with impaired metabolism, even low levels may cause gastrointestinal discomfort such as nausea, bloating, or mild irritation of the gut lining. Research published in International Journal of Molecular Sciences notes that ethanol exposure can also alter gut microbiota composition and increase gut permeability, potentially affecting digestion and immune response. To avoid ethanol residues, choose teas labeled as “flavor-free,” “additive-free,” or “naturally flavored,” and select reputable brands with clear ingredient transparency. For more on ethanol use in food, visit the Food Packaging Forum’s ethanol resource.

44. Sodium Hypochlorite

44. Sodium Hypochlorite
A technician carefully tests surfaces with sodium hypochlorite, highlighting the balance between effective disinfection and material sensitivity. | Generated by Google Gemini

Sodium hypochlorite, the active ingredient in household bleach, is sometimes used in the disinfection of tea bag materials and production equipment to eliminate microbial contamination. While effective for sanitization, this chemical can leave behind residues or form byproducts such as chlorinated organic compounds. The Centers for Disease Control and Prevention (CDC) warns that sodium hypochlorite and its byproducts can be irritating to mucous membranes, including those of the digestive tract.

When tea bags treated with sodium hypochlorite are steeped, trace residues may dissolve into the beverage and be ingested. Research in Nutrients notes that exposure to chlorinated byproducts can disrupt gut epithelial cells, increase gut permeability, and provoke symptoms such as nausea, abdominal pain, or diarrhea, particularly in sensitive individuals. Over time, chronic low-level exposure may impact the gut microbiome and contribute to inflammatory responses. To reduce risk, choose tea brands with “chlorine-free,” “unbleached,” or “chemical-free” processing claims, and favor manufacturers with transparent sanitation protocols. For more on sodium hypochlorite and its effects in food processing, see the Food Packaging Forum’s sodium hypochlorite overview.

45. Polyamide

45. Polyamide
A close-up of polyamide mesh showcases its intricate weave and impressive heat stability under industrial lighting. | Generated by Google Gemini

Polyamide, commonly known as nylon, is frequently used to create mesh tea bags due to its strength, flexibility, and fine filtration capabilities. These mesh bags are popular in premium or pyramid-shaped tea products. While polyamide is designed to be heat-resistant, studies have found that high temperatures during steeping can cause the release of microplastics or small oligomers into the tea. The Food Packaging Forum notes that polyamide materials may degrade or migrate under prolonged exposure to hot water.

Ingested polyamide microplastics or breakdown products can accumulate in the digestive tract, where they have the potential to disrupt gut barrier function and alter the gut microbiome. Research published in Frontiers in Microbiology indicates that exposure to microplastics can lead to inflammation, interference with nutrient absorption, and increased gut permeability. Sensitive individuals may experience digestive discomfort, bloating, or changes in bowel habits with repeated exposure. To reduce risk, choose teas packaged in paper or cotton bags, or opt for loose-leaf tea prepared with stainless steel or glass infusers. For more on polyamide in food packaging, see the Food Packaging Forum’s polyamide resource.

46. Melamine

46. Melamine
Colorful melamine packaging containers are stacked together, raising concerns about potential toxicity in food storage solutions. | Generated by Google Gemini

Melamine is a nitrogen-rich synthetic compound sometimes used in the production of food packaging materials, adhesives, and laminates. While not a standard component of tea bags, melamine may be present in certain tea bag packaging or in containers used for storage and transport. When exposed to hot water or acidic environments, melamine can migrate into tea and be ingested. The U.S. Food & Drug Administration (FDA) has issued warnings about melamine migration and its potential health risks, especially with repeated exposure.

Once ingested, melamine can be absorbed in the digestive tract, where it may cause toxicity. Research published in Frontiers in Pharmacology indicates that melamine exposure can damage the gut lining, provoke inflammation, and contribute to the formation of insoluble crystals that may impair kidney and digestive function. Symptoms of melamine toxicity include abdominal pain, nausea, and, in severe cases, kidney complications. To avoid melamine exposure, choose teas packaged in paper, cotton, or glass, and avoid storing or brewing tea in melamine containers. For more on melamine in food packaging, see the Food Packaging Forum’s melamine overview.

47. Furan Compounds

47. Furan Compounds
A high-tech laboratory setup showcases the processing and absorption analysis of furan compounds using advanced instrumentation. | Generated by Google Gemini

Furan compounds are volatile, potentially toxic chemicals that can form during high-temperature processing of foods and beverages, including tea. Roasting, drying, and certain flavoring procedures may generate furans as byproducts, which can remain in tea leaves and transfer to brewed tea. The European Food Safety Authority (EFSA) and U.S. Food & Drug Administration (FDA) have recognized furan as a substance of concern due to its carcinogenic potential in animal studies.

When tea containing furan compounds is brewed, these chemicals can be absorbed through the gut lining. Research published in Molecules indicates that furan exposure may cause oxidative stress, damage intestinal epithelial cells, and increase the risk of gastrointestinal inflammation and even tumors with long-term or high-level intake. Because furans are formed during thermal processing, their levels are often higher in roasted or instant teas. To minimize exposure, choose teas processed with gentler drying methods, such as air-drying or steaming, and opt for reputable brands that test for contaminants. For more information on furans in food and beverages, see the Food Packaging Forum’s furan resource.

48. Paraffin Wax

48. Paraffin Wax
A close-up of paraffin wax-wrapped string suspended in liquid, illustrating an experiment simulating the process of digestion. | Generated by Google Gemini

Paraffin wax is sometimes used to coat tea bag strings, providing water resistance and smooth handling during packaging and brewing. While paraffin is considered food-grade when refined, it is derived from petroleum and may contain trace impurities. The European Food Safety Authority (EFSA) and U.S. Food & Drug Administration (FDA) allow limited use of food-grade paraffin wax but caution that impurities or excessive ingestion can cause health concerns.

When tea bag strings coated with paraffin wax are submerged in hot water, small amounts of wax or its breakdown products may dissolve into the beverage. Ingesting paraffin wax can lead to digestive irritation, particularly in sensitive individuals, causing symptoms such as nausea, abdominal discomfort, or mild laxative effects. Research published in Current Opinion in Food Science suggests that long-term exposure to mineral oil hydrocarbons, including paraffin wax, could disrupt gut barrier function and potentially influence gut microbiota. To avoid paraffin wax exposure, choose teas with uncoated, natural fiber strings or opt for loose-leaf teas prepared with non-coated utensils. For more on paraffin wax in food contact materials, visit the Food Packaging Forum’s paraffin wax overview.

49. Synthetic Fibers (Nylon)

49. Synthetic Fibers (Nylon)
A close-up view of a nylon pyramid tea bag reveals fine microplastics nestled among fragrant loose tea leaves. | Generated by Google Gemini

Nylon, a synthetic polyamide fiber, is commonly used in the production of pyramid-shaped and premium mesh tea bags due to its strength, transparency, and ability to maintain shape during steeping. However, when exposed to boiling water, nylon tea bags can shed microplastics and oligomers into the brewed tea. A study published in Scientific Reports found that billions of microplastic and nanoplastic particles can be released from a single nylon tea bag during steeping.

Once ingested, these microplastics can accumulate in the digestive tract and potentially disrupt gut health. Research in Frontiers in Microbiology indicates that microplastics may increase gut inflammation, alter the gut microbiome, and impair nutrient absorption. Over time, these changes can weaken the gut barrier, increase susceptibility to digestive disorders, and contribute to systemic inflammation. Sensitive individuals may experience bloating, cramps, or other gastrointestinal symptoms. To reduce exposure to nylon fibers and microplastics, opt for tea bags made of unbleached paper, cotton, or other biodegradable materials, or choose loose-leaf tea with stainless steel or glass infusers. For more on microplastic shedding, consult the BBC’s microplastics in tea bags report.

50. Artificial Sweeteners

50. Artificial Sweeteners
A cup of flavored tea steeps beside a packet of artificial sweetener, highlighting their impact on gut bacteria. | Generated by Google Gemini

Artificial sweeteners such as aspartame, sucralose, or saccharin are sometimes added to flavor-infused or “diet” teas to provide sweetness without calories. While these additives are approved for use by the U.S. Food & Drug Administration (FDA), growing research suggests they can significantly impact gut health. According to a study published in Nature, artificial sweeteners can alter the composition and function of gut bacteria, potentially leading to glucose intolerance, gut dysbiosis, and inflammation.

Regular consumption of artificial sweeteners may disrupt the balance of beneficial gut microbes, weaken immune defenses, and contribute to symptoms such as bloating, irregularity, or discomfort. Sensitive individuals may also experience headaches or allergic reactions. Artificial sweeteners are typically listed in the tea’s ingredients, so check for names like “aspartame,” “sucralose,” “acesulfame K,” or “saccharin” on packaging. To avoid these additives, choose unsweetened teas or those sweetened with natural ingredients such as stevia or honey. For more on the impact of artificial sweeteners on gut bacteria, visit the Harvard Health Publishing’s overview of sweeteners.

Conclusion

Conclusion
A close-up of a tea bag with a bold warning label, highlighting concerns about its impact on gut health. | Generated by Google Gemini

With tea being a daily ritual for billions worldwide, understanding the hidden chemicals in tea bags is crucial for safeguarding your gut health. From microplastics to pesticide residues, many substances may go unnoticed yet have profound effects on your digestive system. To reduce risks, always check for transparent ingredient lists, choose certified organic or “chemical-free” products, and opt for unbleached or plastic-free tea bags. If you experience persistent digestive symptoms, consider consulting a healthcare professional and request gut microbiome screening. Staying informed and vigilant empowers you to enjoy your favorite beverage safely. For additional guidance, consult resources like the Environmental Working Group’s food safety guide.

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