Abstract: O,O-acetyldaurisoline(Adau) is a derivative of daurisoline (Dau). In cultured PC12 cells, Adau was found to inhibit K⁺, Bay K8644 and norepinephrine induced intracellular free calcium concentration increase. Adau was also shown to protect PC12 cells from hypoxiareoxygenation injury with EC₅₀ of 64.3±12.5 μmol·L^-1 by MTT assay. Adau (2.5,5 and 10 mg·kg^-1,iv) administrated 30 min before ischemia in bilateral carotid artery occlusion and four-vessel occlusion rats, attenuated the increase of lipid peroxide content and the decrease of SOD activity. These results show that Adau have significant protective effects aganist ischemic injury.