Abstract: Objective:To study the protective effects of the water extract of Ligusticum chuanxiong on the hypoxic umbilical human vein endothelial cells(EAHY926).Methods:The EAHY926 cell was cultured in vitro,and the hypoxic model of which was establised using physical and chemical methods.After the hypoxic cells was interfered by the water extract of Ligusticum chuanxiong,the viability of cells was determined,and the levels of lactate dehydrogenase(LDH),superoxide dismutase(SOD) and nitric oxide(NO) were detected.Results:High and middle dose water extract of Ligusticum chuanxiong could significantly improve the cell viability,reduce LDH leakage,and increase NO content and SOD activity(P<0.01).Conclusions:The water extract of Ligusticum chuanxiong can significantly antagonize the hypoxia injury of EAHY926,the mechanism of which may involve in removing free radical,increasing NO content and reducing the hypoxic injury.