To investigate the antioxidant capacity of active ingredients of Lycium barbarum leaves (AILBL) and the protective effect of AILBL on acute alcoholic liver injury in mice and to reveal the antioxidant activity of AILBL.The antioxidant capacity of AILBL was determined by ABTS and DPPH methods in vitro.Furthermore,male ICR mice were randomly divided into 6 groups,control group,model group,positive control group silymarin(200 mg/kg,i.g.) and low-middle-and high-dose AILBL groups (30,100,300 g/kg,i.g.,once a day for 1 week).After pre-treatment of AILBL for 1 week,6 g/kg alcohol was administrated by gavage for 3 times to mimic acute alcoholic liver injury.The serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels,hepatic malondialdehyde (MDA) and glutathione (GSH) contents were determined.Liver histopathological changes were examined by H&E and immunohistochemical staining.ABTS as well as DPPH scavenging experiments in vitro showed that AILBL and was better than trolox on scavenging DPPH·.In the model of alcohol-induced liver injury mice,AILBL pretreatment dramatically reduced the serum ALT and AST levels,decreased hepatic MDA content and increased hepatic GSH content.In addition,AILBL alleviated the hepatocytes inflammation and necrosis induced by alcohol.Immunohistochemical analysis showed that AILBL inhibited the expression of CYP2E1,HIF-1α and iNOS induced by alcohol,and AILBL reduced the accumulation of ROS induced by ethanol in vitro.AILBL exerts strong antioxidant capacity in vitro and exhibits the protective effects on acute alcoholic liver injury in mice,and the mechanism of action is probably associated with the improvement of endogenous antioxidant activity and the reduction of lipid peroxidation of mice.