Q: 70 year old chinese male with history of Atrial fibrillation and on warfarin presented with acute symptoms of stroke. Patient's family reports that patient is very health conscious and takes his warfarin faithfully. Actually, he recently brought some traditional medicines from china. What could be the probable culprit?



Answer: Ginseng

In one double-blind, four-week trial, 20 healthy volunteers received warfarin, 5 mg, daily for three days during week one and week four. Beginning in week two, 12 subjects took 2 gram of powdered ginseng in capsules, while the other eight volunteers received placebo capsules.

After two weeks, daily doses of ginseng significantly reduced the blood levels and the anticoagulant effects of warfarin. Compared with the placebo group, the ginseng group had significantly reduced INR and peak plasma warfarin level.

Brief Communication: American Ginseng Reduces Warfarin's Effect in Healthy Patients - A Randomized, Controlled Trial - Annals of Internal Medicine, July 6, 2004 vol. 141 no. 1 23-27