Objective:To investigate the effect of BuYanHanWu (BYHW) Tang upon infarction,vessel damage penumbra (VDP),fibrinolytic system activity and endothelin.Methods:BYHW Tang consists of two parts,invigorationg Qi section (IQs) and promoting blood flow section (PBFs).To utilize the model of cold photochemical initiation of thrombosis to observe the effects of the whole of BYHW Tang,IQs and PBFs,respectively,on infarction size,VDP size,degree of vessel damage,localized cerebral blood flow,plasma tissue plasminogen activator(t-PA),plasminogen activator in hibitor (PAI) and plasma endothelin content.Result:BYHW Tang influences all indexes significantly.IQs and PBFs both have the actions of limiting infarction size and degree of vessel damage,promoting of cerebral blood flow and inhibiting PAI activity.On the other hand,reducing the size of VDP and increasing the activity of t-PA by BYHW Tang come mainly from IQs,and the effect of reducing ET content is based on PBFs.Conclusion:The IQs is emphasized in the priscription of BYHW Tang.It can enhance the activity of fibrinolytic system and reduce the VIP size.The result hints BYHQ Tang is not only formulated for stroke caused by deficiency of Qi,but also effective for the treatment of ischemic stroke.