To test the cytoprotective effect of sophorae radix (SR) against hydrogen peroxide (H₂O₂)-induced cytotoxicity, we investigated the cell viability using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay in the presence of ethyl acetate subfractions of SR water extracts In H9c2 cells. And to clarify the cytoprotective mechanism of SR extracts, we evaluated the cellular glutathione (GSH) contents in the presence of subfraction 1, 2, 3, and 4 of SR ethyl acetate soluble fractions. Among 1 -12 subfractions of SR ethyl acetate soluble fractions, 1, 2, 3 and 4 subfractions have an efficacy inhibiting the cytotoxicity induced by H₂O₂ in H9c2 cells. Also, the protective effects of 1, 2, 3 and 4 subfractions of SR ethyl acetate soluble fractions resulted from the anti-oxidant effects. These results suggest that ethyl acetate soluble fractions of SR water extracts is effective in the prevention of H₂O₂-induced cytotoxicity and 1, 2, 3 and 4 subfraction of ethyl acetate soluble fractions possess the anti-oxidant component.