AIM: The transforming growth factor-beta (TGF-β)/Smad signaling pathway system plays a prominent role in the control of cell growth and extracellular matrix formation in the progression of liver fibrogenesis. Smad proteins can either positively or negatively regulate TGF-β responses.In this study, the therapeutic effects of Chinese traditional compound decoction, JinSanE, and the changes of TGF-β/Smad signaling pathway system in carbon tetrachloride (CCl4)-induced rat experimental liver fibrosis were examined.METHODS: Seventy-two healthy Wistar rats were assigned to groups including normal control group, CCl4model group, JinSanE treatment group Ⅰ and JinSanE treatment group Ⅱ. Each group contained 18 rats. All groups, except the normal control group, received CCl4subcutaneous injection for 8 wk. Rats in JinSanE groups Ⅰand Ⅱ were orally treated with JinSanE daily at the 1st and 5th wk, respectively, after exposure to CCl4. The expression of TGF-β1 and TGF-β1 type Ⅱ receptor (TRⅡ) mRNA in the liver was determined by reverse transcription polymerase chain reaction, and the expression of TGF-β1,Smad3 and Smad7 by immunohistochemistry. The liver histopathology was also examined by HE staining and observed under electron microscope. The activities of several serum fibrosis-associated enzymes, alanine aminotransferase (ALT), aspartate aminotransferase (AST), the levels of serum hyaluronic acid (HA) were assayed.RESULTS: Hepatic fibrosis caused by CCl4 was significantly inhibited in the JinSanE-treated groups. The degrees of necrosis/degeneration and fibrosis scores were significantly lower in the JinSanE-treated groups than in the model control group. The expression of TGF-β1, TRⅡ and Smad3was significantly higher in the model group than that in the JinSanE-treated groups, and the active/total TGF-β1ratio in the JinSanE groups was suppressed. Expression of TRⅡ mRNA and Smad3 proteins showed a distribution patt similar to that of TGF-β1 with a direct correlation in terms of the degree of hepatic fibrosis. The amount of positive staining Smad7 cells was significantly less in the model group than in the JinSanE-treated groups and the normal group. The contents of ALT, AST and HA were significantly lower in the JinSanE-treated groups than those in the model group.CONCLUSION: Traditional Chinese medicine, JinSanE,prevents the progression of hepatic damage and fibrosis through the inhibition of TGF-β1, TRⅡ and Smad3 signal proteins,and increases wxpression of Smad7 signal protein in vivo.