Objective : Yinjinchunggan-tang(YJCGT) is reported previously as having theraputic effects on hepatitis such as anti-implammatory, anti-apoptotic, anti-viral(HBV), etc. Though this prescription is not studied on its anti-fibrogenic effect, it is still expected to have the effect in the liver. Thus, this study was performed to investigate the anti-fibrogenic effect of YJCGT on thioacetamide(TAA)-induced liver fibrosis in rats. Method: Rat liver fibrosis was induced by intraperitoneal TAA injection(150mg/kg) 3 times a week for 5 weeks. After the YJCGT (YJCGT 1g/kg, YJCGT 2g/kg)-treatment, body weight, liver and spleen weights, liver function test, the complete blood count and the portal pressure were studied. In addition, gene expressions of ASMA, procollagen type Ia2, MMP2, TIMP1 and TIMP2, all of which are known to be associated with liver fibrosis, were analyzed by RT-PCR. After YJCGT (YJCGT 1g/kg, YJCGT 2g/kg) treatment, percentages of collagen in TAA-induced rat liver tissue were measured by image analyzer. Results : The body weight of the normal group increased more than that of the control and YJCGT-treated groups. The AST level of the YJCGT lg/kg-treated group significantly decreased compared to that of the control. The ALT and the GGT levels of the YJCGT 2g/kg-treated group significantly increased compared to those of the control. In the YJCGT-treated groups. WBC, RBC and Hgb elevated by TAA injection decreased but platelet count increased. In the YJCGT lg/kg-treated group, the portal pressure elevated by TAA injection significantly decreased. The significant decreases in the gene expressions of procollagen type Ia2, MMP2 and TIMP2 were observed in the YJCGT-treated groups. In histological findings. TAA injections caused severe liver fibrosis, but the YJCGT treatment significantly reduced the amounts of hepatic collagens. Conclusions: These results suggest that YJCGT has beneficial effects on the treatment of patients with liver cirrhosis as well as chronic hepatitis. Further study should be done to decide the optimal concentration of the YJCGT for the treatment of liver cirrhosis.