garlic and garlic cloves

Q. Last year I was diagnosed with atrial fibrillation. I am now on warfarin and understand I will have to take it for the foreseeable future. I have regular blood tests to make sure my blood is clotting properly.

A few months ago I began taking garlic, thinking that it would help my heart. Shortly after I started, my blood work changed dramatically. Although I stopped the garlic pills, it took a good while for my blood to return to normal.

Are there any other herbs, supplements or OTC drugs that can affect warfarin?

A. Dozens of herbs and supplements have been suspected of interacting with the anticoagulant warfarin (Coumadin). Some include:

Chamomile, Coenzyme Q10, Cranberry, Danshen, Garlic, Ginger, Ginkgo, Ginseng, Grapefruit, Green Tea and  St. John’s wort

Your experience with garlic suggests that it could interact dangerously with warfarin. Other natural remedies that might alter this anticoagulant’s action include ginger, ginkgo and feverfew. There are a number of case reports in the medical literature suggesting that garlic may raise INR levels (a measure of blood clotting). This could increase the risk for bleeding.

You can find more information on warfarin interactions in our free guide at this link.

One potential interaction with warfarin that many health professionals overlook is acetaminophen (Tylenol). Although it has been known for decades that taking acetaminophen for more than a few days while also taking warfarin could raise INR levels, most patients are not warned about this risk. Remember, when INR goes up too high, there is an increased risk for a bleed or even a life-threatening hemorrhage.

An occasional Tylenol or two for a headache should not pose a significant problem. The concerns goes up, however, if someone takes acetaminophen for more than two or three days in a row.

Another worry would be any NSAID-type pain reliever. That includes aspirin, ibuprofen or naproxen. Aspirin together with warfarin could interact to increase the risk of bleeding. The problem with other NSAIDs is that they can cause lesions in the stomach. These are far more likely to turn into life-threatening bleeding ulcers if there is warfarin on board.

The bottom line is to check with a physician and pharmacist before adding anything, including herbs or OTC drugs, to a warfarin regimen. Do check out our free guide to get an overview of this problem.

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  1. Ann

    I think half of you are crazy coming off the medicine for blood thinning. Should do as Doctor tells you. 3/4 are mixing herbs and ect. That you should know will interfere. OH! yea listen to these crazy people on internet. That’s smart!!!!!

  2. Barbara

    Does manukau honey interact with warfarin

  3. tiffiany
    morganton n.c

    I have AFIB the dr’s tried to put me on blood thinners. I wore monitor for seven days the next day after taking the warfine.

    I started vaginal bleeding for no reason nothing there to bleed.

    I put my self on organic vinegar with mother in it I use two tablespoons of the vinegar and a table spoon of raw honey and put in microwave for 2 minutes to melt.

    The honey makes a good tea and a natural blood thinner, plus a chewable baby aspirin works wonders to keep the blood thin.

  4. Sandra

    I had a clot in my brain that caused a stroke but have full recovery now they have me on a baby aspirin and blood pressure pills irregular heart beat and dr it me on 80 mil lipotor but because of readings taken me off for 2 weeks but now says I have to take warrfarin. I would rather take natural blood thinners but scarred if I don’t follow dr advice I’ll have another stroke! Do all people who have stroke have to go on blood thinners?

  5. Nancy

    I am on warfarin for 14 years. I et spinach. Garlic and drink green tea once a day. That’s why u ppl are having problems. Food can never replace pills. That’s why ppl get complications. I don’t take aspirin. Cause I know the interaction. If it was rat poison, why am I still alive and have controlled warfarin? If u don’t like ur doc change it and stop whinning.

    • christine currie

      garlic and spinach bad with blood thinners!

      Stop calling people mean words.

  6. jo c

    I have afib and I find magnesium helps. I also use apple cider vinegar. have been able to cut down on Coumadin. anyone tried this?

    • SA
      Tehran, Iran

      Well said! My mom was diagnosed with Afib and has been taking Warfarin (Coumadin) for two years now. I’m feeling so sad because it’s too hard for us to control the blood clot measures such as PT (by repetitive blood tests, and interactions with a dozen other medications, and the specific diet).

      Also, in Iran, the country where I live, doctors are into business and do not empathize with the patient. They are, FOR THE MOST PART (if not ONLY), engaged in business and making money from the patients. Last month my mom was diagnosed with arthritis, and the doctor prescribed two NSAIDs together (Piroxicam and Naproxen), and IF I HAD NOT googled the interactions on web (specifically at, she would have used that for a month.

      The doctor had also prescribed 3 dexamethasone injections (once per week) and calcium+magnesium+zinc tablets, while my mom did not suffer from a major pain (she had pain while combing hair and lifting shoulder or turning the neck but was not suffering from that), so I asked her to avoid it ALL.

      Now, I am surfing the web for APPLE CIDER VINEGAR and its possible interaction with Warfarin. so I came across this website, since one of the comments have thrown a hint on this ELIXIR! I appreciate his/her comment and would appreciate any further help on ACV experience with Warfarin. I am sorry for this rather poor conduct in English.

  7. Cindy M. B.

    If you study up on AF, you’ll find many references to NSAIDS, to wit: they don’t only cause the stomach ulcers and possible bleeding, but they reputedly are a risk factor for developing AF in the first place! So sad, because I really like NSAIDS for body aches associated with sports, but it’s now on my taboo list…. The AF is now resolved, and I sure don’t want it to come back!

    • SA
      Tehran, Iran

      the doctor who prescribed two NSAIDs together! for my mom did definitely know that she is taking warfarin pills for two years. my mom told him very explicitly that she is on warfarin and asked “are you sure this prescription would not interact with warfarin?” it’s horrible and shameful. Sarah A, Iran

  8. MLB

    What about platelet thinners, such as Effient? Tylenol is the only pain killer I’m not allergic to!

  9. Rosy

    Cinnamon thins your blood. This blood thinning properties are particularly high in Cassia Cinnamon, while Ceylon Cinnamon does not seem to thin your blood. This blood thinning property of Cassia Cinnamon helps it in acting as an anti clotting agent especially for those suffering from heart disease. However care must be taken to NOT to take it with any other blood thinning medication, including aspirin.

  10. jpmoiseqc

    what about XARELTO same problems?

  11. fbl
    Las Vegas, NV

    Why stay on the rat poison rather than natural blood thinners? I found this system accidentally when the rat poison didn’t work on me at all and the drugs Xarelto and Eliquis caused some dramatic side effects. I’m still suffering from the side effects six months after stopping the blood thinners. My family Dr. has checked my blood and it is doing fine.

    I’m taking garlic (Kyolic), cayenne, nattokinase, vitamin E, and Omega 3. I have no nasty bruising on my body and the blood is good.

  12. Diana Ward

    Would the same interaction happen with the newer blood thinners?

    • SA
      Tehran, Iran


      If you mean Dabigatran, I guess Warfarin is better than Dabigatran. You would find the details at this article, please:

      Also, I am thinking about purchasing a point of care PT checkup analyzer for my mom to use at home. She is keen to have it checked at the hospital. She is right, and it’s quite reasonable. But I’m willing to suggest that she have this POC device for weekly checks at home BESIDES the hospital-based Warfarin test.

      Hospital checks, I guess, are more reliable. I would only suggest it, and my dear mom would make the final decision.

  13. Jennifer

    It was helpful to read above that acetaminophen is Tylenol. Could you similarly provide the names the brands are ibuprofen and naproxen? I realize one can read labels, but it would be helpful for the readers here to be provided this helpful information. Thanks.

  14. Cindy
    northern California

    About 4 years ago I determined to figure out why my mother-in-law {95 years old at the time} almost never got out of bed anymore. She had been walking at least 1/2 mile a day regularly. The change seemed to have come on too quickly to be ‘just old age’. I should mention that I am her legal guardian. I learned that a stint in the hospital for a UTI had introduced 2 new prescriptions for her. Her only health issue is high blood pressure. A doctor put her on Warfarin and on a Beta Blocker because of her atrial fibrillation. She tried to tell them she had this irregular heart beat all her 95 years but they would not listen. I wrote the two doctors and told them I was weaning her off of these medications because they were making her life not worth living. Instead, I did some research and have her taking Slo-Magnesium and a spoonful of Black Strap Molasses. She will be 100 in May. She does a little jig behind her walker to demonstrate her joy in living.

    • SA
      Tehran, Iran

      oh Cindy, I’m so sorry for that shameful mistake and I’m happy that you could solve the problem. beta blockers such as propranolol interact dangerously with warfarin.
      Cindy, how could I attempt to have my parents live long like your mother in law, please? my mom is on just a myriad of medicine (blood pressure, minor depression, Afib, thyroid, cholestrol, arthritis, …) she is not suffering from obesity.

  15. Virginia

    I have a severe case of bronchitis and used a menthol cough drops for my cough. Menthol is not compatible with Warfarin and caused a nose bleed. Warfarin and Cumadin have to be the most dangerous drugs ever. I do take 6 arthritis Tylenol a day for pain and have had no bleeding episodes. Taking Tylenol for pain is just above a notch of taking nothing.

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