Platelets aggregation and thrombosis formation are major reasons of cardiovascular and cerebral vascular diseases.To develop new generative,potent and safe agents for inhibiting platelet aggregation and preventing above diseases are urgently required.Some traditional Chinese medicines of″Houxue Huayu″have been shown to inhibit platelet aggregation potently.In the present study the mechanisms and the molecular targets of puerarin,salvianolic acid B and the analogue of 3-n-butylphthalide,dl-PHPB were investigated and compared with ticlopidine.Four platelet aggregation inducers,ADP,arachidonic acid,collagen and thrombin were used in the study.It was found that puerarin and dl-PHPB specifically inhibited ADP induced platelet aggregation like ticlopidine did.However,salvianolic acid B inhibited both ADP and collagen induced platelet aggregations with similar potency.Due to existing two ADP receptor subtypes on platelets,P2Y1 and P2Y12,we studied the action of above compounds on the receptors and the signaling pathways.It was found that dl-PHPB decreased IP1 accumulation produced by ADP,but had no effect on IP1 level induced by m-3M3 FBS,an activator of PLC.M-3M3 FBS might attenuate the inhibitory effect of dl-PHPB on ADP-induced platelet aggregation.In addition,dl-PHPB did not affect cyclic AMP formation in platelets by ADP,which is different from P2Y12 antagonist ticlopidine.Puerarin showed the similar effects of dl-PHPB.Therefore,the actions of dl-PHPB and puerarin might be through P2Y1receptor-PLC-βpathway.Salvianolic acid B did not reduce the IP1 accumulation stimulated by ADP.It might act on the receptor subtype P2Y12.Our results suggest that components of Chinese herb medicine might be a resource for development of novel anti-platelet drugs. Platelets aggregation and thrombosis formation are major reasons of cardiovascular and cerebral vascular diseases. To develop new generative, potent and safe agents for inhibiting platelet aggregation and preventing above diseases are urgently required. Home traditional Chinese medicines of “Houxue Huayu” have been shown to inhibit platelet aggregation potently.In the present study the mechanisms and the molecular targets of puerarin, salvianolic acid B and the analogue of 3-n-butylphthalide, dl-PHPB were investigated and compared with ticlopidine. Four platelet aggregation inducers, ADP, arachidonic acid, It was found that puerarin and dl-PHPB specifically inhibited ADP induced platelet aggregation like ticlopidine did. However, salvianolic acid Bated both ADP and collagen induced platelet aggregations with similar potency. Due to existing two ADP receptor subtypes on platelets, P2Y1 and P2Y12, we studied the action of above compounds on the rece ptors and the signaling pathways. It was found that dl-PHPB decreased IP1 accumulation produced by ADP, but had no effect on IP1 level induced by m-3M3 FBS, an activator of PLC. M-3M3 FBS might attenuate the inhibitory effect of dl -PHPB on ADP-induced platelet aggregation.In addition, dl-PHPB did not affect cyclic AMP formation in platelets by ADP, which is different from P2Y12 antagonist ticlopidine. Puerarin showed the similar effects of dl-PHPB.Therefore, the actions of dl -PHPB and puerarin might be through P2Y1 receptor-PLC-βpathway. Salvianolic acid B did not reduce the IP1 accumulation stimulated by ADP. It might act on the receptor subtype P2Y12 .Our results suggest that components of Chinese herb medicine might be a resource for development of novel anti-platelet drugs.