Objectives : The aim of this study was to investigate the hepatoprotective effect of Soshiho-tang (SSH) in mouse primary liver cells against hydrogen peroxide ($H_2O_2$)-induced oxidative stress. We also elucidated the molecular mechanism of hepatoprotective effect by SSH. Methods : Cell viability, level of ALT, AST and LDH, intracellular ROS level, mRNA expression and activity of antioxidant enzymes were used to evaluate hepatoprotection of SSH against $H_2O_2$. Target gene expressions were analyzed by real-time PCR. Results : Pre-treatment with SSH for 1 hour prevented cytotoxicity against $H_2O_2$. $H_2O_2$-induced ROS level decreased under SSH pre-treatment. mRNA expression of GPx and SOD increased in SSH-treated cells. In addition, HSP72 and HSP40 gene expression were elevated under SSH-treatment. Conclusions : These results indicate that SSH protects mouse primary liver cells from $H_2O_2$-induced oxidative injury. This hepatoprotective activity of SSH is mediated by decreasing intracellular ROS and increasing antioxidant enzyme expression (GPx and SOD) and stress response protein (HSP72 and HSP40).