Herbal Tea, Acid Reflux, Teeth and Iron Absorption
What the sources say about peppermint tea and heartburn, acidic herbal teas and tooth enamel, and tea tannins and iron absorption, and where the evidence is thin.
Content last updated . This page has not been medically reviewed.
Safety first. Natural products can cause side effects and interact with medicines. Read herbal tea and extract safety before you use anything on this page.
Three everyday effects, three different levels of evidence
These are not emergencies, but they are common reasons people ask whether an herbal tea is a good daily habit. Each section says what was studied (a tea, a lab test, a different drink) because the answer changes with the form. Nothing here is a reason to stop a prescribed medicine; ask the prescriber or pharmacist.Acid reflux and heartburn
Regulator view. The European monograph on peppermint leaf (EMA/HMPC, revised 2020) says people with gastroesophageal reflux (heartburn) should avoid peppermint leaf preparations because heartburn may increase, and it lists worsening reflux as an undesirable effect, with the frequency not known. It also advises caution for people with gallstones or other bile-duct problems. [1] The monograph covers peppermint leaf as a herbal tea and as tinctures; it is a regulatory statement, not a trial result.NIH. The NIH page on peppermint says peppermint tea made from the leaves appears to be safe, and that long-term safety of large amounts of peppermint leaf is unknown. [2] The same page lists heartburn as a possible side effect of peppermint oil taken by mouth, which is a different product. [2]
Other herbal teas. NIH lists heartburn as a possible side effect of ginger taken by mouth; the page is mainly about ginger supplements, not tea. [3] NHS lists coffee, tomatoes, alcohol, chocolate and fatty or spicy foods as things that can cause or worsen heartburn, and advises avoiding foods and drinks that trigger your symptoms. [4] The NHS page we read does not mention herbal tea.
Trials of tea. Proper evidence not found. We searched PubMed for peppermint with reflux and the lower esophageal sphincter, herbal tea with reflux, and mint tea with heartburn and found no trial of an herbal tea on reflux symptoms. An unrelated survey of plants used in drinks was the only hit for mint tea. So the cautions above are regulatory and reported, not measured in tea trials.
What a reader can do. Watch whether a particular tea brings on heartburn and mention it to a pharmacist or clinician. NHS suggests seeing a GP if heartburn happens most days. [4] See peppermint tea, heartburn and reflux and the herbal tea safety essentials.
Teeth: acid and enamel
This evidence is from laboratory studies, not from people tracking their dental health.| Study | What it found | Strength and limits |
|---|---|---|
| 2003 laboratory study in the Journal of Dentistry | The pH of the herbal teas tested ranged from 3.1 to 7.1, and many were more erosive to enamel than orange juice. [5] | Preclinical (lab); a screen of products, not a measure of real-life tooth wear |
| 2001 laboratory study on extracted teeth | A herbal tea of the type tested and a black tea both eroded enamel; the authors concluded regular use is likely to matter. [6] | Preclinical (lab); one herbal tea tested; 21 teeth per group |
These studies tested particular products, and a lower pH means more acid. They did not test every herbal tea, and we did not find a human study connecting daily herbal tea to cavities or tooth wear. Proper evidence not found for people. The papers do not let us say which teas on today's shelves are more or less acidic; check with a dentist. A dentist can say whether your own habits are a concern.
Iron absorption
Tea contains polyphenols and tannins that can bind iron. The sources we read differ in how directly they answer for herbal tea.- NHS advises people with iron-deficiency anemia to eat and drink less tea, coffee and milk, because large amounts make it harder to absorb iron. [7] The page says "tea" without naming herbal tea.
- Laboratory analysis (1994): yerba mate, tea and oregano had the highest tannin content among herbal infusions common in Chile and other Latin American countries, and the authors concluded that drinking herbal teas at or around meals may inhibit absorption of iron, zinc or copper. [8] This measured tannin in the leaves, not iron in people.
- Human trial (2020): in 17 Senegalese mother-child pairs, an herbal tea made from Combretum micranthum decreased iron absorption from a wheat-based meal. [9] That plant is a regional herbal tea, not a common supermarket blend. It is small, and the result should not be carried to other teas.
- Population studies point different ways. A French study of black, green and herbal tea found no link with iron stores in healthy adults. [10] A Kenyan study of women of childbearing age found that more cups of tea was associated with iron deficiency; the abstract does not say which teas. [11] Cross-sectional studies cannot show cause.
Takeaway: the best evidence for iron is for tea in general and for one regional herbal tea. For common teas such as chamomile or peppermint, Proper evidence not found in the sources we read. If you have low iron, take iron pills or are pregnant, ask a clinician or pharmacist about timing and tea. Related pages: iron, anemia and iron deficiency and herbal tea and medicine interactions.
Frequently asked questions
Is peppermint tea bad for acid reflux?
The European peppermint leaf monograph says people with reflux should avoid peppermint leaf preparations because heartburn may increase. [1] We found no trial of peppermint tea on reflux. If it worsens your symptoms, tell a clinician.
Can herbal tea damage tooth enamel?
Laboratory studies found some herbal teas eroded enamel, and some were more erosive than orange juice. [5][6] Proper evidence not found for effects on people's teeth.
Does tea block iron absorption?
NHS advises people with iron deficiency anemia to drink less tea because it makes iron harder to absorb. [7] A trial of one herbal tea found lower iron absorption from a meal. [9] A French study found no link in healthy adults. [10]
Does the time of day I drink tea matter for iron?
A 1994 laboratory paper suggests herbal teas at or around meals may inhibit absorption of iron, zinc and copper. [8] Ask a pharmacist how this fits your iron supplement, if you take one.
Should I stop a medicine if tea upsets my stomach?
No. NHS says not to stop any prescribed medicine without speaking to a doctor first. [4] Talk to the prescriber or pharmacist.
References
- European Medicines Agency (EMA), Committee on Herbal Medicinal Products (HMPC). European Union herbal monograph on peppermint leaf, EMA/HMPC/572705/2014, revised 15 January 2020. Read 2026-10-23.
- National Center for Complementary and Integrative Health (NIH). Peppermint Oil: Usefulness and Safety. Read 2026-10-23.
- National Center for Complementary and Integrative Health (NIH). Ginger: Usefulness and Safety. Read 2026-10-23.
- NHS (England). Heartburn and acid reflux. Read 2026-10-23.
- Phelan J, Rees J. The erosive potential of some herbal teas. J Dent, 2003 (laboratory study). Read 2026-10-23.
- Brunton PA et al. The erosive effect of herbal tea on dental enamel. J Dent, 2001 (laboratory study on extracted teeth). Read 2026-10-23.
- NHS (England). Iron deficiency anaemia. Read 2026-10-23.
- Pizarro F et al. Factors which modify the nutritional state of iron: tannin content of herbal teas. Arch Latinoam Nutr, 1994 (laboratory analysis; abstract in English). Read 2026-10-23.
- Ndiaye NF et al. Polyphenol-rich tea decreases iron absorption from fortified wheat bread in Senegalese mother-child pairs. Eur J Clin Nutr, 2020 (trial, 17 mother-child pairs). Read 2026-10-23.
- Mennen L et al. Consumption of black, green and herbal tea and iron status in French adults. Eur J Clin Nutr, 2007 (cross-sectional study). Read 2026-10-23.
- Nyakundi PN et al. Consumption Pattern of Tea Is Associated with Serum Ferritin Levels of Women of Childbearing Age in Nandi County, Kenya. Ann Nutr Metab, 2024 (cross-sectional study). Read 2026-10-23.