The effect of water extract from Acori graminei Rhizoma (AGRW) on the activities of phase II, glutathione S-transferase (GST), and antioxidant, glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD), enzymes in liver of ICR mice was assessed. Following intragastric application of AGRW to mice for 14 days, the changes of GST, GSH-Px, and SOD activities and glutathione (GSH) content were investigated. GST activity in liver of mice was increased with the treatment of AGRW. The extract application to mice also resulted in increase of GSH levels. GSH-Px activity was remarkably increased in liver. Increasing concentrations of AGRW in intragastric application from 10 to 250 mg/kg body weight increased SOD activity. The results in this study suggest that Acori graminei Rhizoma has detoxification and antioxidant activities.