Abstract: Objective: To investigate the protective effect of Wuzhiyin (WZY) against acetaminophen (AP) induced hepatic injury in mice. Methods: Male KM mice were randomly divided into blank group, model group, low, medium and high dose WZY groups (100, 200, 400 mg/kg). The normal saline of equal volume was used in the blank group and model group. In addition to the blank group, the other groups were given AP (300 mg/kg) on the 6th day to establish the model of liver injury in mice. Calculate the organ index to detect alanine aminotransferase (ALT), aspartate aminotransferase (AST) in serum and malondialdehyde (MDA), glutathione (GSH), TNF-α, IL-6, IL-1β level, combined with liver tissue sections to observe pathological changes. Results: The liver index of the mice in the low, medium and high dose group were significantly lower than that in the model group (P<0.05 or P<0.01). Compared with the model group, the serum AST, ALT, TNF-α, IL-6, IL-1β in the medium-, high- dose group significantly decreased (P<0.05 or P<0.01). The content of GSH in the medium-, high- dose group significantly increased, while the content of MDA significantly decreased. Histopathological HE and Tunel staining showed that WZY could improve the necrosis and apoptosis of liver tissue, and reduce the inflammatory infiltration of cells. Conclusion: WZY had certain protective effect on acetaminophen-induced acute liver injury, and its mechanism might be related to its antioxidant effect, reduction of inflammation and inhibition of cell apoptosis.