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Ingredient guide

Chamomile side effects, and who should be careful

Written by the Full Measure editorial team, which sells supplements. Approved for publication by the Full Measure owners. Updated .

Drafted with AI assistance from the sources listed below. How we write these

Quick answer

Chamomile side effects are uncommon. NCCIH lists nausea, dizziness and allergic reactions, which are severe in some people and more likely in those allergic to ragweed and related plants. Interactions with warfarin have been reported, and chamomile might make birth control pills less effective. Ask first if you are pregnant or breastfeeding.1,2

Key facts

  • Ten sleep trials reported no adverse events, but most relied on people to report problems themselves.3
  • NIH's liver injury database has no cases of chamomile harming the liver.4
  • Reactions are more likely if you are allergic to ragweed, chrysanthemums, marigolds or daisies.1
  • In healthy volunteers not taking blood thinners, a week of strong chamomile tea did not change clotting tests.5

Side effects reported

Side effects are uncommon. Nausea and dizziness have been reported.1

In trials, side effects have mostly been no more common than with placebo. In the US sleep trial, adverse events were mild, short-lived and no more frequent with chamomile, and in a trial lasting up to 38 weeks the rates were similar to placebo.6,7

In a 12-week trial, two women taking chamomile capsules stopped because of mouth sores, skin spots and itching.8

Only one of the 10 sleep trials in a 2024 review checked the purity or strength of the chamomile it used, and most recorded side effects only when people reported them.3

Allergy, skin and eyes

Allergic reactions can occur, including severe reactions (anaphylaxis) in some people. They are more likely in people allergic to ragweed, chrysanthemums, marigolds or daisies.1,9

Chamomile on the skin can cause an allergic rash, and drinking the tea has made existing rashes worse in people already sensitized to it. Used near the eyes, it may cause irritation.1,9

Chamomile may cross-react with other members of the aster family, including echinacea, feverfew and milk thistle. If one of these has given you a reaction, ask before trying chamomile.9

Skin reactions can follow products applied to the skin, not just tea. Two women developed a rash on the nipples after using an ointment containing Roman chamomile, and patch tests confirmed chamomile as the cause.9

Medicines

Ask your pharmacist or doctor first

Interactions between chamomile and warfarin have been reported. In one published case, a woman taking warfarin was admitted to hospital with internal bleeding after using chamomile tea and lotion. The warfarin label asks for more frequent INR blood tests whenever an herbal product is started or stopped.1,2,10,11

Reported in studies

In 12 healthy volunteers who were not taking blood thinners, a week of chamomile tea (9 bags a day) or extract capsules did not change standard blood clotting tests.5

Those volunteers were not taking warfarin, so the result does not apply to people who are. Ask your pharmacist or doctor before combining the two.5

Ask your pharmacist or doctor first

Chamomile might have some of the same effects as estrogen. NCCIH says preliminary studies suggest that taking chamomile with birth control pills might make the pills less effective.1

Reported in studies

Two more possible interactions come from NCCIH. In theory, chamomile could deepen the drowsiness caused by sedatives, and some medicines broken down by the liver have been reported to interact with it.1

Pregnancy, breastfeeding, babies and children

Little is known about chamomile in pregnancy or while breastfeeding. NIH's lactation database has no data on its safety in nursing mothers or infants, though it judges the small amounts expected in breast milk unlikely to harm a baby at usual doses.1,9

The same database notes that Clostridium botulinum (botulism) spores have been found in some loose leaf chamomile teas sold in health food stores. Ask a pediatrician before giving a baby any herbal tea.9

For children, NCCIH rates chamomile possibly safe by mouth over the short term, but no children's dose has been set.1

Chamomile might have some estrogen-like effects. For that reason NCCIH says it might worsen any condition sensitive to estrogen, such as breast or uterine cancer.1

What's in ours

What’s in ours

  • Sleep: Chamomile Extract, 100 mg per serving, from the label

Questions people ask

Are chamomile side effects different for men?

The side effects reported, nausea, dizziness and allergic reactions, apply to men and women alike. We found no side effect specific to men in the sources we reviewed.1

Can you become allergic to chamomile tea after drinking it before?

Yes. Allergy can develop after earlier exposure, and drinking chamomile tea has caused severe reactions in people who had become sensitized. Stop, and get urgent help for any swelling or trouble breathing.9

Is chamomile hard on the liver?

No liver injury has been linked to chamomile in LiverTox, NIH's database of liver harm from medicines and supplements.4

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Sources

  1. National Center for Complementary and Integrative Health. Chamomile. Bethesda (MD): National Institutes of Health. Last updated November 2024. Opened 2026-10-07.
  2. Segal R, Pilote L. Warfarin interaction with Matricaria chamomilla. CMAJ. 2006;174(9):1281-1282. Opened 2026-10-07.
  3. Kazemi A, Shojaei-Zarghani S, Eskandarzadeh P, Hashempur MH. Effects of chamomile (Matricaria chamomilla L.) on sleep: A systematic review and meta-analysis of clinical trials. Complement Ther Med. 2024;84:103071. Opened 2026-10-07.
  4. Chamomile. In: LiverTox: Clinical and Research Information on Drug-Induced Liver Injury. Bethesda (MD): National Institute of Diabetes and Digestive and Kidney Diseases; 2012 onward. Updated May 24, 2022. Summary read through PubMed. Opened 2026-10-07.
  5. Schwartz JA, Romeiser JL, Kimura R, et al. Effect of chamomile intake on blood coagulation tests in healthy volunteers: a randomized, placebo-controlled, crossover trial. Perioper Med (Lond). 2023;12(1):51. Opened 2026-10-07.
  6. Zick SM, Wright BD, Sen A, Arnedt JT. Preliminary examination of the efficacy and safety of a standardized chamomile extract for chronic primary insomnia: a randomized placebo-controlled pilot study. BMC Complement Altern Med. 2011;11:78. Opened 2026-10-07.
  7. Mao JJ, Xie SX, Keefe JR, et al. Long-term chamomile (Matricaria chamomilla L.) treatment for generalized anxiety disorder: A randomized clinical trial. Phytomedicine. 2016;23(14):1735-1742. Opened 2026-10-07.
  8. Mohsenzadeh-Ledari F, Agajani Delavar M, Moghadamnia AA, et al. Efficacy and safety of Matricaria chamomilla intervention in managing menopausal symptoms: a triple-blind clinical trial. Menopause. 2025;32(4):353-358. Opened 2026-10-07.
  9. Chamomile. In: Drugs and Lactation Database (LactMed). Bethesda (MD): National Institute of Child Health and Human Development; 2006 onward. Updated February 15, 2021. Read through PubMed. Opened 2026-10-07.
  10. Tan CSS, Lee SWH. Warfarin and food, herbal or dietary supplement interactions: A systematic review. Br J Clin Pharmacol. 2021;87(2):352-374. Opened 2026-10-07.
  11. Warfarin sodium tablets: prescribing information (Amneal Pharmaceuticals). DailyMed, U.S. National Library of Medicine. Published June 3, 2026. Opened 2026-10-07.

This page is information, not medical advice. Talk to your doctor or pharmacist about your own situation.