Objectives: In traditional medicine, Wolgukwhan has been used for the treatment of digestive system disease, such as indigestion, brash, ructation, nausea and vomiting. This study was purposed to investigate the effects of Wolgukwhan methnol extract (WGWM) on oxidative liver cell injury. Methods: In vivo assay, we administerated acetaminophen(500mg/kg, i.p.) to starved mice 24hrs after pretreatment of WGWM for 6days. In the liver homogenates, lipid peroxide and glutathione(GSH) levels were measured. In addition, activities of hepatic enzyme, such as catalase, glutathione peroxidase(GPX), glutathione S-transferase(GST) were measured in the hepatic mitochondrial and cytosolic fractions. Results: In vivo administeration of WGWM showed effective inhibition of acetaminophen induced lipid peroxidation and elevations of glutathione level. The acetaminophen treatment resulted in a decrease of catalase, GPX and GST activities. By contrast, WGWM pretreatment increased compare to those of untreated groups. Conclusions: These results suggested that WGWM might protect against lipid peroxidation by free radicals, destruction of hepatic cell membranes.