Antifibrinolytic therapy during major complex surgery could reduce blood loss and allogeneic transfusion. Novel antagonists of the plasminogen activator and the corresponding model system are of clinical importance. In this paper (1S,2'S,3S)-1-[2-(S)-carboxylindolemethylenemethineaminoeth-1-yl]-2,3,4,5-tetrahydropyrolo[1,2:1,6]pyrazino[3,4:2,3]-1,2,3,4-tetrahydrocarboline-2,5-dione (CIPPC) was presented as a novel antagonist of plasminogen activator, and its blood coagulation and action mechanism were investigated by using a model system which consisted of a mouse-tail bleeding assay, in vitro and in vivo fibrinolysis inhibition assays, a thrombus formation assay and a plasminogen (PLG) electrophoresis assay.