Objective:To observe the effects of Yinchenhao Decoction (茵陈蒿汤) for non-alcoholic steatohepatitis (NASH) in rats and study the mechanism.Methods:Total 18 male SD rats were randomly divided into a normal control group,a model group and a treatment group,6 rats in each group.Rats in the model and treatment groups were fed with high-fat forage for 10 weeks to prepare the NASH model,and the rats in the treatment group were administrated with Yinchenhao Decoction from the 6th week for 5 weeks.All rats were sacrificed at the end of the l0th week and the samples were collected.Serum alanine aminotransferase (ALT) activity,tumor necrosis factor-α (TNF-α) level,and hepatic triglyceride (TG) and free fatty acid (FFA) contents were determined.Hepatic pathological changes were detected by HE staining.Results:Serum ALT activity,TNF-α level,hepatic TG and FFA contents,and the fatty deposition in hepatocytes were significantly reduced in the rats of the treatment group.Conclusion:Yinchenhao Decoction has good therapeutic effects for NASH,protecting the liver function and reducing the fatty deposition in liver,which are possibly related with reduction of FFA content and inhibition of TNF-α expression.