Feverfew may alter the effects of some prescription and non-prescription medications. If you are currently being treated with any of the following medications, you should not use feverfew without first talking to your health care provider.
Blood-thinning medications -- Feverfew may inhibit the activity of platelets (a substance that plays a role in blood clotting), so individuals taking blood-thinning medications (such as aspirin and warfarin) should consult a health care provider before taking this herb.
Feverfew; Tanacetum parthenium