Effects of aqueous extract of Ganoderma lucidum, collected in Kyoto (K) and Odawara (O), on the experimentally disseminated intravascular coagulation (DIC) in rats were investigated. K prevented the decreases of blood platelet and fibrinogen, the prolongation of prothrombin time and the increase of fibrin degradation products (FDP) at a dose of 500 mg/kg in normal rats on DIC induced by endotoxin. O prevented the decrease of blood platelet at a dose of 500 mg/kg. K and O prevented the formation of hepatic vein thrombosis induced by endotoxin in hyperlipemia rats. In order to reveal the mode of in vivo action of K and O, the activities of K and O for blood platelet aggregation, thrombin action and fibrinolytic action were examined in vitro. K and O showed inhibitory effects on blood platelet aggregation induced by collagen, and on thrombin action at concentrations of 500-1000 μg/ml.