Objective: To observe the protective effect and mechanism of Xiaoyao San on rats’ acute liver injury induced by the decoction of Tripterygium wilfordii. Method: Sixty rats were randomly divided into control group

T. wilfordii model group

ganlixin group

low-dose

medium-dose and high-dose groups of Xiaoyao San. Each group was respectively fed with the corresponding dose of drug for 5 days. Then fed with decoction of T. Wilfordii for 4 days to make the model.alamine aminotransferase(ALT)

aspartate aminotransferase(AST)

superoxide dismutase(SOD)

malondialdehyde(MDA) and glutathione peroxidase GSH-Px in serum were measured and liver pathology is detected. Result: Compared with the control group

the serum ALT

AST and MDA of model group were significantly increased

SOD and GSH-Px decreased obviously(P<0.05). Pathological investigation showed liver fatty change and turbid degeneration. Compared with model group

all doses of Xiaoyao San could effectively decrease ALT

AST and MDA

increase GSH-Px (P<0.05)

medium-dose and high-dose also increase SOD (P<0.05)

the liver injury was alleviated. Conclusion: T. wilfordii-induced acute liver injury is associated with lipid peroxidation. Xiaoyao San has effect of protecting the liver injury induced by T. wilfordii and the mechanism has a relationship with inhibition of lipid peroxidation.