Jowiseungcheongtang(JST) has been in Sasang constitution medicine for many years as a therapeutic agent for cerebral disease. But the effect of Jowiseungcheongtang(JST) on neurotoxicity is not known. The purpose of this study was to determine the effects of Jowiseungcheongtang(JST) on the hippocampal cell injured by Xanthine Oxidase/Hypoxanthine. The results were as follows: 1. XO/HX decreased the survival rate of the cultured hippocampal cells on NR assay and MTT assay. 2. JST water extract have efficacy of decreasing a amount of lipid peroxidation increased by XO/HX in cultured hippocampal cells. 3. JST water extract have efficacy of increasing DNA synthesis decreased by XO/HX in cultured hippocampal cells. From the above results, It is concluded that JST has marked efficacy in preventing cultured hippocampal cells from the damages by XO/HX.