Mume Fructus extract is used in folk medicine in Eastern Asian countries including Korea. However, its therapeutic effect on thrombosis is not known. Mume Fructus methanol extract (ME) dose-dependently inhibited ADP-induced platelet aggregation and also exhibited about 130% fibrinolytic activity compared to the natto. Oral administration of ME to mice significantly extended tail-bleeding time. ME prolonged both aPTT and PT in human citrated plasma also. These results suggest that the methanol extract from Mume Fructus have antithrombosis activity.