AIM: To study the effect of WeiJia on chronic liver injury using carbon tetrachloride (CCl4) induced liver injury animal model.METHODS: Wistar rats weighing 180-220g were randomly divided into three groups: normal control group (Group A), CCl4 induced liver injury control group (Group B) and CCl4 induction with WeiJia treatment group (Group C). Each group consisted of 14 rats. Liver damage and fibrosis was induced by subcutaneous injection with 40% CCl4 in olive oil at 3 mL/kg body weight twice a week for eight weeks for Groups B and C rats whereas olive oil was used for Group A rats. Starting from the third week,Group C rats also received daily intraperitoneal injection of WeiJia at a dose of 1.25 μg/kg body weight. Animals were sacrificed at the fifth week (4 male, 3 female), and eighth week (4 male, 3 female) respectively. Degree of fibrosis were measured and serological markers for liver fibrosis and function including hyaluronic acid (HA), type Ⅳ collagen (CIV), γ-glutamyl transferase (γ-GT), alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were determined. Alpha smooth muscle actin (α-SMA) and proliferating cell nuclear antigen (PCNA) immunohistochemistry were also performed.RESULTS: CCl4 induction led to the damage of liver and development of fibrosis in Group B and Group C rats when compared to Group A rats. The treatment of WeiJia in Group C rats could reduce the fibrosis condition significantly compared to Group B rats. The effect could be observed after three weeks of treatment and was more obvious after eight weeks of treatment. Serum HA, CIV,ALT, AST and Y-GT levels after eight weeks of treatment for Group C rats were 58±22 μg/L (P<0.01), 57±21 μg/L (P<0.01), 47±10 U/L (P<0.01), 139±13 U/L (P<0.05) and 52±21 U/L (P>0.05) respectively, similar to normal control group (Group A), but significantly different from CCl4 induced liver injury control group (Group B). An increase in PCNA and decrease in a-SMA expression level was also observed.CONCLUSION: WeiJia could improve liver function and reduce liver fibrosis which might be through the inhibition of stellate cell activity.