Objectives : This study was carried out to examine toxic effect of Sintongchukeo-tang on cultured mouse spinal sensory neurons inhibited by neurotoxicity induced by hydrogen peroxide. Methods : MTT assay, NR assay, LDH and neurofilament assay were performed after spinal sensory neurons were preincubater with various concentrations of Sintongchukeo-tang water extract before treatment of cells with hydrogen peroxide. Results : Hydrogen peroxide induced ceil degeneration such as the decrease of cell viability was measured by MTT and NR assay in the cultured mouse spinal sensory neurons. Sintongchukeo-tang water extract was effective in the decrease of LDH activities of neurons produced by hydrogen peroxide. Sintongchukeo-tang water extract was effective in the increase of amount of neurofilaments damaged by hydrogen peroxide. Conclusions : From the above results, it is suggested that hydrogen peroxide induces the inhibition of cell viability in cultured mouse spinal sensory neurons and Sintongchukeo-tang water extract was effective in cultured neurons damaged by hydrogen peroxide.