OBJECTIVE To study the protective effects o f valproic acid on cardiac and cerebral injury in rats subjected to severe scalding combined with seawater immersion injury with delayed fluid replacement. METHODS The rats were divided into scalding+delayed fluid replacement group （group S ），scalding+seawater immersion+delayed fluid replacement group （group SS ）， scalding+seawater immersion+valproic acid+delayed fluid replacement group （group SSV ）according to random number table ，with 60 rats in each group. All groups were subjected to 35％total body surface area third-degree full-thickness scalding with boiled water. Group SS and group SSV were immersed in artificial ；seawater（30 min）immediately after scalding ，and group SSV was subcutaneously injected with valproic acid 300 mg/kg immediately after out of water. Sodium lactate Ringer ’s 0314-2279277。E-mail：125467374@qq.com injection was injected intravenously within 30 minutes according to 1/2 Parkland formula at 2 h after scalding in each group for delayed fluid replacement. The death time of rats was recorded ，and the average survival time and 24 h survival rate of rats in each group were calculat ed. Mean arterial pressure （MAP），heart rate （HR），respiration rate （RR），rectal temperature （RT），arterial blood pH ，arterial partial pressure of oxygen （PaO2），arterial blood partial pressure of carbon dioxide （PaCO2），HCO3－，creatine kinase MB isoenzyme （CK-MB）and neuron specific enolase （NSE）were detected before scalding ，at 0，2，5 h after scalding. The pathological changes of cardiac and cerebral tissue were observed. RESULTS The 24 h survival rate of group SS （55％）was significantly lower than that of group S （90％）， while that of group SSV （75％）was increased significantly ，compared with group SS （P＜0.05）. Compared with group S ，the levels of MAP ，RT，HR，pH，PaO2 and HCO 3－ in group SS were significantly lowered ，while the levels of CK-MB and NSE were increased significantly at 0，2，5 h after scalding ；the levels of PaCO 2 were increased significantly at 2，5 h after scalding ， while the levels of RR were decreased significantly at 0，2 h after scalding （P＜0.05）. Compared with group SS ，the levels of MAP，RT，HR，pH，PaO2 and HCO 3－ in group SSV were significantly increased ，while the levels of PaCO 2，CK-MB and NSE were decreased significantly at 2，5 h after scalding ；the level of RR was increased significantly at 2 h after scalding （P＜0.05）. At 2，5 h after scalding ，cardiac and cerebral injury of rats in group SS were aggravated significantly than that in group S ；cardiac and cerebral injury of rats in group SSV were relieved significantly than that in group SS. CONCLUSIONS After severe scalding combined seawater immersion injury ，hypodermic injection of sodium valproate could protect cardiac and cerebral function of rats ， improve vital signs and blood gas index ，prolong survival time and improve survival rate in rats.