Can I Take These?

Can You Take Omega-3 / Fish Oil and Warfarin Together?

NIH's own fact sheets name warfarin as the one documented drug interaction for omega-3 supplements, due to a possible added bleeding/anticoagulant effect.

MonitorEvidence: High

See the full Omega-3 / Fish Oil page and Warfarin page for other reviewed interactions and reference information.

What the interaction means

NIH ODS's Health Professional fact sheet has a section titled "Interactions with Medications" that gives exactly one example, warfarin: "Fish oil can have antiplatelet effects at high doses... Fish oil might prolong clotting times, as indicated by an elevated international normalized ratio (INR), when it is taken with warfarin, but most research indicates that doses of 3-6 g/day fish oil do not significantly affect the anticoagulant status of patients taking warfarin." The consumer fact sheet states more simply: "high doses of omega-3s may cause bleeding problems when taken with warfarin (Coumadin®) or other anticoagulant medicines."

Why it may happen

Fish oil can have antiplatelet effects at high doses (described by the source as less potent than aspirin), which can add to warfarin's own anticoagulant effect and, in some cases, elevate INR.

Practical context

The evidence is nuanced rather than a blanket warning: most research on typical fish-oil doses (3-6 g/day) does not find a significant effect on anticoagulant status, and FDA-approved omega-3 pharmaceutical package inserts state that trials "have not produced 'clinically significant bleeding episodes.'" However, those same package inserts recommend periodic INR monitoring for patients taking omega-3 products alongside anticoagulants, which is why this is rated "monitor" rather than "avoid." Anyone on warfarin should tell their prescriber before starting omega-3/fish oil supplements, especially at higher doses.

What the sources say

Omega-3 Fatty Acids - Health Professional Fact Sheet — NIH Office of Dietary SupplementsOmega-3 Fatty Acids - Consumer — NIH Office of Dietary Supplements

Last reviewed 2026-08-24

Medical information disclaimer: this information is general and educational. It does not diagnose conditions, prescribe treatment, or determine whether a combination is safe for you personally. Follow your prescription label and ask a pharmacist or clinician before starting, stopping, or combining products. Full disclaimer.

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