Naoxing oral preparation has ho formed to be effective for ischemic stroke by preliminary clin-ical trial. To find a safe, efficient and convenient preparation Naoxing nasal spray was developed. Theeffect of Naoxing nasal spray on increasing hypoxic toleance of brain cells and improving blood circulationwas confirmed in this experiment. Twenty-eight guinea Pigs were randomly allocated to 4 groups: Group A(Naoxing nasal spray),Group B (ninodipine injection intraperitoneally), GrouP C (ligushazine injectionintrqperitoneally) and Group D(distilled water for nasal spray). After the medication for 4 days, acutecerebral ischemia was produced by the occlusion of bilatelal caretid arteries for 45 minutes. Serum NO lev-el,superoxide dismutase(SOD), glutathione superoxidase (GSH--Px) and lipid peroxide (LPO) levelsin cerebral tissue were detected. Ultrastructure of right hippocampus was oberved.The results showedthat NO, SOD, GSH-Px level in Group A is significantly higher and LPO level is significantly lower thanthere in Group D(P0.05).The damage of neuron, gliocyte and capillary under electron microscope was less thanGroup D,the differences being not significant as compared with Group B and C. It is concluded that theeffect of Naoxing nasal splay is as ed as ninodipine and ligustazine injection.