[Warfarin effects diminishment by the Clostridium butyricum preparation after cardiac surgery; report of a case].

: A 55-year-old gentleman diagnosed with severe aortic insufficiency and annuloaortic ectasia underwent modified Bentall procedure using mechanical valve. Anticoagulation therapy with warfarin was introduced after surgery, but sufficient anticoagulation effect was not achieved with a large amount of dosage. After discontinuing the use of the Clostridium butyricum preparation on postoperative day 29, sufficient anticoagulationt effect was obtained within several days. Clostridium butyricum might change the vitamin K production in the intestinal bacterial flora and attenuated the anticoagulation effect of warfarin.