Objective To investigate the antithrombosis effects of Buyang Huanwu Decoction(BHD) and its active fractions on cultured vascular endothelial cells(VEC) following the stimulation of thrombin and their mechanism.Methods The human umbilicus vein endothelial cells(ECV 304) were cultured in media containing 10 U/mL thrombin and different dosese of drugs.The levels of tPA and PAI-1 were detected by ELISA,the expression of TF,TFPI,and TM mRNA was measured by RT-PCR,and the expression of PKC? was examined by immunohistochemical staining 24 h later.Results Compared to the control without any treatment,the release of tPA was increased evidently(P0.05).Compared to the data after the mere stimulus of thrombin,each dose of BHD increased the release of tPA(P0.05);And glycoside(1.25 mg/mL) increased the release of tPA(P