Does Flaxseed Interact With Warfarin?

In our latest question and answer, the pharmacist discusses whether or not flaxseed interacts with warfarin.


Is there any problem with eating flaxseed and taking warfarin?

Asked by Chuck On Mar 10, 2023

Answered by
Medical Content Reviewed By HelloPharmacist Staff

Published Mar 10, 2023
Last updated Mar 10, 2023

Key points

  • Studies are mixed on whether flaxseed consumption increases the risk of bleeding while taking anticoagulants (e.g., warfarin).
  • Studies show that flaxseed may have mild anticoagulant effects in some individuals (e.g., diabetics) but has little to no effect in this regard in others.
  • Theoretically, taking flaxseed with warfarin could increase bleeding risk, although the chance of this occurring is unlikely. Nevertheless, be sure to always look out for signs and symptoms of bleeding.

Quick Answer

Studies are mixed in regard to whether or not flaxseed consumption increases the risk of bleeding while taking anticoagulant or antiplatelet drugs (like warfarin and clopidogrel). The risk of a serious interaction is unlikely but it is important to be monitored and look out for signs and symptoms of bruising/bleeding if you do take them together.

Detailed Answer

Coumadin (warfarin) is an anticoagulant medication prescribed to prevent blood clots. In familiar terms, it is known as a 'blood thinner'.

Flaxseed, which comes from the flax plant, is small, oval-shaped, and can be consumed in a variety of ways, including ground, whole, or oil form. The seeds are known for their many health benefits due to their high content of essential fatty acids, fiber, and other nutrients.

Flaxseed is rich in essential fatty acids, specifically alpha-linolenic acid (ALA) which belongs to the omega-3 family of fatty acids, and linoleic acid (LA) which belongs to the omega-6 family of fatty acids. These fatty acids are essential because our body cannot produce them and they must be obtained through our diet.

ALA can be converted into eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), which are the long-chain omega-3 fatty acids found in fatty fish. Omega-3 fatty acids have been found to be beneficial for cardiovascular health, inflammation, and cognitive function, while omega-6 fatty acids are important for maintaining the integrity of cell membranes and helping with immune function.

However, EPA and DHA have been associated with having a mild blood thinning effect.

Blood-Thinning Effects?

The answer of whether or not flaxseed interacts with warfarin is not straightforward, and more research is needed to draw definitive conclusions.

There is some evidence to suggest that flaxseed may have mild anticoagulant (i.e., blood-thinning) effects, but these findings are mainly limited to diabetic patients according to one study. Most studies in healthy individuals have not found significant changes in platelet aggregation or overall coagulation after supplementing their diet with flaxseed oil.

Although flaxseed contains alpha-linolenic acid (ALA), which is similar to the omega-3 fatty acids found in fish oils that are known to inhibit platelet aggregation (and ALA can be converted to these omega-3 fatty acids), many studies have not found any changes in platelet aggregation after supplementing with flaxseed for one to three months.

One study even compared the effects of supplementing with ALA from flaxseed oil versus EPA and DHA from fish oil in healthy individuals and found no significant differences in bleeding time, plasma fibrinogen concentration, or other coagulation factors between the two groups.

Only a few studies have reported some changes in platelet aggregation with flaxseed consumption, but more research is needed to draw definitive conclusions on whether ALA affects bleeding times. The ratio of omega-3 to omega-6 polyunsaturated fatty acids contained in flaxseed is likely a significant factor in regulating how our blood clots.

Final Words

In summary, there is a theoretical possibility that the fatty acids in flaxseed may have a mild anticoagulant effect, which could increase the risk of bleeding when combined with blood-thinning drugs like warfarin.

However, most studies have shown that flaxseed does not affect blood coagulation in healthy individuals.

To be safe, it's important to inform your doctor about all the supplements and medications you are taking, including flaxseed, so you can be monitored. As always, it's also important to be mindful of any signs of easy bruising or bleeding when taking warfarin.


  • Plant and marine derived (n-3) polyunsaturated fatty acids do not affect blood coagulation and fibrinolytic factors in moderately hyperlipidemic humans, PubMed
  • The cardiovascular effects of flaxseed and its omega-3 fatty acid, alpha-linolenic acid, PubMed
  • Supplementation with flaxseed oil versus sunflowerseed oil in healthy young men consuming a low fat diet: effects on platelet composition and function, PubMed
  • Alpha-linolenic acid in the treatment of rheumatoid arthritis. A double-blind, placebo-controlled and randomized study: flaxseed vs. safflower seed, PubMed
  • Flaxseed Cysteine Protease Exhibits Strong Anticoagulant, Antiplatelet, and Clot-Dissolving Properties, PubMed
  • A Comparative Study of the Effect of Flaxseed Oil and Sunflower Oil on the Coagulation Score, Selected Oxidative and Inflammatory Parameters in Metabolic Syndrome Patients, PubMed

About the Pharmacist

Dr. Brian Staiger, PharmD

Dr. Brian has been practicing pharmacy for over 13 years and has wide-ranging experiences in many different areas of the profession. From retail, clinical, program development, and administrative responsibilities, he's your knowledgeable and go-to source for all your pharmacy and medication-related questions! Dr. Brian Staiger also has herbalist training and educational certificates in the field of medical ethnobotany. Feel free to send him an email at! You can also connect with Dr. Brian Staiger on LinkedIn.

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