The purpose of this study is to examine the toxic effects caused by xanthine oxidase/hypoxanthine (XO/HX) and the effects of herbal extracts such as Mangeum-tang (萬金湯: MGT) and Gamimangeum-tang (加味萬金湯: GMGT) on the treatment of the toxic effects. The results of these experiments were XO/HX, an oxygen radical-generating system, decreased the survival rates of the cultured cells on XTT assay, the amount of DNA syntheses, and the amount of neurofilaments, and increased c-fos positive cells, MGT and GMGT have the efficacy of increasing the survival rates of the cultured cells by increasing the amount of neurofilaments and DNA synthesis and decreasing the c-fos positive cells damaged by XO/HX, From the above results, it is suggested that MGT and GMGT have marked efficacy as a treatment for the damages caused by the XO/HX-mediated oxidative stress. And MGT and GMGT are thought to have certain pharmacological effects.