Drug interactions with warfarin can be dangerous and although common d
rug interactions are now well recognized those with Chinese herbs are
not widely appreciated. 'Danshen' is a herbal medicine often used for
various complaints, particularly cardiovascular, in the Chinese commun
ity. We report a case of danshen-induced overcoagulation with severe a
nd dangerous abnormalities of clotting in a patient with rheumatic hea
rt disease.