Objective To investigate the protective effects of ethyl docosahexaenoate on brain oxidative injury and edema induced by cerebral ischemic/reperfusion in gerbils. Methods The gerbils were subjected to both common carotid arteries occlusion. The contents of MDA and GSH, the activities of GSH-PX, CAT, SOD and ATPase, the water content and the concentrations of Na + and Ca 2+ were measured. Histopathological examination was also done. Results The pretreatment with E-DHA significantly prevented the raise of MDA level, the decline of GSH content, the activities of GSH-Px, CAT, ATPase and the increases of Ca 2+, Na + and water content. Conclusion E-DHA has protective effect on brain ischemic injury and edema, which may be due to an inhibitory action on hydroxyl radical formation and brain edema.