Abstract: OBJECTIVE To investigate the protective effect of 7-HEC against hypobaric hypoxia(HH) induced brain injury in rats. METHODS Fifty two ♂ Wistar rats were divided in to normal group, model group, acetazolamide group and 7-HEC group, 13 rats per group. The drugs were intragastrically administrated for 5 consecutive days, except normal group, the rats in other three groups were transferred to 8 000 m in a HH chamber for 24 h after the final administrated. The brain histomorphology of rats were detected by HE staining. Hydrogen peroxide(H₂O₂), malondialdehyde(MDA), superoxide dismutase(SOD), catalase(CAT), glutathione peroxidase(GSH-Px) and ATPase were evaluated using related Kits. The expression of Bcl-2, Bax and cleaved caspase-3 were assessed with Western blotting. RESULTS Compared to normal group, HH induced brain damage as evidenced by the increased level of H₂O₂ and MDA and the decreased of the activity of antioxidant enzyme including SOD, CAT and GSH-Px as well as Na⁺-K⁺-ATPase, Ca²⁺-Mg²⁺-ATPase. Pretreatment with 7-HEC could reverse these changes. Moreover, 7-HEC could inhibit the apoptosis induced by HH via up-regulating the expression of Bax and caspase-3 and down-regulating the expression of Bcl-2. CONCLUSION 7-HEC can suppress the HH-induced brain damage in rats by alleviating oxidative stress, inhibiting apoptosis and improving energy metabolism.