Does warfarin interact with any herbal supplements?

Yes: Warfarin is the most common drug to show a change in effectiveness with the use of herbal supplements. Among them, st. John's wort and ginko biloba are the most commonly reported to interact with warfarin, the first increases the risk of clotting while the second increases the risk of bleeding.

Yes: Warfarin will interact with any substance that increases risk of bleeding. These incude vitamin k, garlic, possibly ginger, evening primrose, and possibly gingko. As a general rule, warfarin reacts with a lot of other substances. Be careful of other things you're taking when you're on it.