Educational reference of documented concerns — not a personalized safety check and not a clearance to combine. Confirm with your prescriber or pharmacist.
Reviewed supplements
- MajorWarfarinVitamin K supplement (not dietary greens) Vitamin K directly antagonizes warfarin mechanism. 2 PMIDsverified 2026-08-18
- MajorWarfarinGinkgo biloba Ginkgo antagonists platelet-activating factor and case reports plus a large VA cohort show elevated bleeding signals (HR 1. 3 PMIDsverified 2026-08-18
- MajorWarfarinSt John's wort (Hypericum perforatum) Enzyme induction by hyperforin accelerates the metabolism of warfarin, pushing INR down below the protective window. 1 PMIDverified 2026-09-12
- ModerateWarfarinGarlic extract (allicin or aged garlic) Garlic inhibits platelet aggregation, which adds to warfarin anticoagulation rather than opposing it; electronic health record screening flags garlic among warfarin-relevant supplements. 2 PMIDsverified 2026-08-18
- ModerateWarfarinVitamin E, high dose (400 IU+/day) High-dose vitamin E has antiplatelet-type effects; higher serum vitamin E tracks with bleeding risk in patients on oral anticoagulants. 1 PMIDverified 2026-08-18
- CautionWarfarinPanax ginseng (Korean red ginseng) A randomized trial in patients with cardiovascular disease found Korean red ginseng did not significantly change INR with warfarin; case-based concerns remain, so the level is low but documented. 1 PMIDverified 2026-08-18
- CautionWarfarinHigh-dose fish oil (3 g+ EPA+DHA per day) High omega-3 doses reduce platelet aggregation; a retrospective cohort of fish oil with warfarin found no significant INR or adverse-event change, so the documented concern is low-grade. 1 PMIDverified 2026-08-18
Not in this list
A supplement missing from this list has not been reviewed against Warfarin on this site. That is not a statement that combining it is safe.