Quick answer
Ask your pharmacist or doctor before combining. NIH says interactions between chamomile and warfarin have been reported, and a 2021 review lists chamomile tea among items that may raise bleeding risk. A one-week trial in 12 healthy people not taking warfarin found no change in clotting tests, so it does not answer the question for people who do.1,2,3
Key facts
- NIH's complementary health center says interactions between chamomile and warfarin have been reported.1
- One published case describes a woman taking warfarin who was admitted to hospital with multiple internal bleeds after using chamomile tea and body lotion.4
- A systematic review of 149 reports lists chamomile tea among the foods and herbs that may raise bleeding risk with warfarin.2
- In a randomized trial, 12 healthy volunteers who were not taking warfarin had no change in prothrombin time or INR after a week of chamomile tea or capsules.3
- The warfarin label asks for more frequent INR monitoring when botanical products are started or stopped, and it does not name chamomile.5
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.1,2,4,5
Reported in studies
What does NIH say about chamomile and warfarin?
NIH's National Center for Complementary and Integrative Health says interactions between chamomile and warfarin, and between chamomile and some drugs processed by the liver, have been reported. It adds that anyone who takes medicine should talk with a health care provider before using chamomile or other herbal products.1
The same page rates chamomile as likely safe in the amounts found in teas and other foods. That rating is about people in general. It is not a finding about people taking a blood thinner, and the page gives no amount, product type or time frame for the warfarin reports.1
What have studies and reports found about chamomile tea and warfarin?
| Source | What it found | What it cannot tell you |
|---|---|---|
| NIH fact sheet on chamomile | Interactions with warfarin have been reported. | How often, at what amount, or with which form. |
| Case report, 2006 | A woman taking warfarin was admitted to hospital with multiple internal bleeds after using chamomile tea and body lotion. | It describes one person. The authors wrote that no such cases had been reported before and called the risk theoretical. |
| Systematic review, 2021 | Lists chamomile tea among foods and herbs that may raise bleeding risk with warfarin. | It gathers published reports. It is not a controlled test of chamomile. |
| Randomized crossover trial, 2023 | In 12 healthy volunteers, a week of chamomile tea (nine bags a day) or extract capsules did not change prothrombin time, INR or other clotting tests compared with placebo. | The volunteers were healthy and not taking warfarin, and the trial lasted one week. |
| Warfarin label | Asks for more frequent INR monitoring when botanical products are started or stopped. | It does not name chamomile. |
Why would chamomile affect warfarin?
The authors of the case report offer a possible explanation. They write that chamomile is thought to contain coumarin compounds, which gives a theoretical way for it to add to warfarin's effect.4
The warfarin label adds a practical difficulty. It says few adequate, well-controlled studies of botanicals with warfarin exist, and that botanical preparations are not standardized, so the amount of active ingredient can vary. That makes any single cup or capsule hard to predict.5
Does it matter if it is tea, a capsule or a lotion?
The sources give only a partial picture. The reported case involved tea and a body lotion together, so it does not separate the two. The 2023 trial tested tea and capsules in people who were not on warfarin. NIH's statement covers chamomile in general. No source here compares forms in people taking warfarin.1,3,4
None of the sources gives an amount of tea at which a problem begins, so a general rule about a cup a day would be a guess. Mention every form you use, including lotions and tea blends that list chamomile, when you talk to your pharmacist.
What does the warfarin label ask for when an herbal product is started or stopped?
The label tells prescribers to perform more frequent INR monitoring when starting or stopping other drugs, including botanicals. The INR is the blood test used to set the warfarin dose. The patient section tells people not to take or stop any herbal product except on a physician's advice.5
MedlinePlus likewise asks people to tell their doctor and pharmacist about vitamins, nutritional supplements and herbal products, because some of them may increase the risk of bleeding while taking warfarin. Its list of named herbal products does not include chamomile, which is not a finding either way.6
What to ask your pharmacist about chamomile and warfarin
- Does my INR need an extra check if I start or stop drinking chamomile tea?
- Does it matter whether I use tea bags, loose tea, capsules or a lotion?
- Do any teas or supplements I use contain chamomile as part of a blend?
- Which signs of bleeding should I report right away?
Questions people ask
Does chamomile tea interact with warfarin?
NIH says interactions between chamomile and warfarin have been reported, and a 2021 review lists chamomile tea among items that may raise bleeding risk. A small trial in healthy people not on warfarin found no change in clotting tests, so ask your pharmacist about your own case.1,2,3
Can you take chamomile tea with warfarin?
Ask your pharmacist or doctor first, because the sources cannot answer for you. None gives an amount of tea that matters, and the warfarin label asks for more frequent INR checks when a herbal product is started or stopped.5
Is there a chamomile and warfarin interaction?
Reported, but not well measured. There is one published case, a review of reports, and NIH's note that interactions have been reported. The trial found for this page was done in people not taking warfarin.1,2,3,4
Can you take chamomile with warfarin if it is a capsule rather than tea?
The sources do not compare forms in people taking warfarin. The trial that tested capsules enrolled healthy people who were not taking it, so ask your pharmacist.3
Does chamomile tea interact with blood thinners other than warfarin?
The sources on this page are about warfarin. They do not address other blood thinners, which is not a finding either way, so ask your pharmacist about yours.
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Sources
- National Center for Complementary and Integrative Health. Chamomile. Bethesda (MD): National Institutes of Health. Last updated November 2024. Opened 2026-10-07.
- 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.
- 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.
- Segal R, Pilote L. Warfarin interaction with Matricaria chamomilla. CMAJ. 2006;174(9):1281-1282. Opened 2026-10-07.
- Warfarin sodium tablets: prescribing information (Amneal Pharmaceuticals). DailyMed, U.S. National Library of Medicine. Published June 3, 2026. Opened 2026-10-07.
- MedlinePlus. Warfarin. MedlinePlus Drug Information, U.S. National Library of Medicine. Last revised March 15, 2026. Opened 2026-10-11.
This page is information, not medical advice. Talk to your doctor or pharmacist about your own situation.