This study was performed to prove the antithrombotic effects of paeonia japonica (赤芍葯, PJ) aqua-acupuncture solution by way of experimental methods. the thrombosis was induced by injection of collagen the mixture (0.1ml/10g, 2mg/kg B.W) plus serotonin (5mg/kg B.W) into the caudal vein of rats, 2 hours after liquid extract of paeonia japonica (PJ) was acupunctured into 'Taechung' (太衝:Liv3) of rats. The effect of aqua- acupunctures of paeonia japonica (PJ) was examined by the number of RBC and platelets, bleeding time, blood clotting time, death rate, platelet aggregation, plasma coagulation factor activity, exvivo and vitro fibrinolytic activicty of englobulin fracture in the rats. The results were summerized as followings. 1. The number of RBC and platelets was significantly increased in PJ-treated group in comparison with the control group. 2. Bleeding time was significantly shortened in PJ-treated group in comparison with the control group. 3. Blood clotting time was significantly prolonged in PJ-treated group in comparison with the control group. 4. The death rate of mouse was inhibited in PJ-treated group in comparison with the control group. 5. The platelet aggregation was inhibited in PJ-treated group in comparison with the control group. 6. The prothrombin time and activated partial thromboplastin time on the test of plasma coagulation factor activity was prolonged but was not valuable in PJ-treated group. 7. Fibrinogen lyses time of rat was reduced and lyses area was increased in PJ-treated group in comparison with the control group. 8. Fibrinogen lyses time of rat in vitro assay was reduced in PJ-treated group. From the above results, it was thought that the aqua-acupuncture of PJ could be applied effectively in the thrombosis.