To evaluate the protective effect of the aqueous extracted from Dioscorea nipponica Makino (AEDN) on carbon tetrachloride (CCl4)-induced acute liver injury in mice by regulating Keap1/Nrf2 signal pathway.Methods:Dioscorea nipponica Makino was extracted and concentrated by water and dried to be powder,which was AEDN.The content of polysaccharide in AEDN was determined by ultraviolet visible (UV) spectrophotometery.The male Kunming mice were adiminstrated with AEDN for 7 days,and then acute liver injury was induced by intraperitoneal injection of 0.3% CCl4 olive oil solution.The effect of AEDN on oxidative stress indexes in CCl4 induced liver injury mice and the regulation effect of AEDN on Keap1/Nrf2 signal pathway were evaluated.Results:The extraction rate of AEDN was 9.64%,and the polysaccharide content was (53.03±0.70)%.In CCl4-induced mice actue liver injury,AEDN significantly decreased the level of MDA and increased the level of SOD,GSH and GSH-Px in liver tissue of mice.The mechanism of action study found that the protein levels of T SOD1,SOD2,Nrf2,GST,NQO1 and HO-1 were all markedly up-regulated,and the level of Keap1 was down-regulated.The mRNA level of iNOS were also suppressed by AEDN treatment.Conclusion:AEDN has protective effect on CCl4-induced acute liver injury in mice via adjusting Keap1/Nrf2 signaling pathway.