The antithrombic activity of ginsenoside-Ro isolated from the roots of Panax ginseng C. A.MEYER was evaluated in experimental models of disseminated intravascular coagulation (DIC)induced by infusion of endotoxin or thrombin in rats. Ginsenoside-Ro (50 mg/kg, p.o.) prevented the decrease of fibrinogen in endotoxin-induced DIC. Ginsenoside-Ro also inhibited the formation of fibrin thrombi in the renal glomeruli in thrombin-induced DIC.Ginsenoside-Ro showed a promotive effect on the activation of the fibrinolytic system as determined by the euglobulin lysis time (ELT) assay. The promotive effect of ginsenoside-Ro on the activation of the fibrinolytic system was inhibited by pretreatment with e-aminocaproic acid (an anti-plasmin agent), but not by pretreatment with promethazine or cyproheptadine (anti-chemical agents).