AIM: To investigate the efficacy of a Chinese medicine, Yi-gan-kang granule (granules for benefiting the liver), in prophylaxis and treatment of liver fibrosis in rats and its possible mechanism.METHODS: One hundred and forty Sprague-Dawley rats were randomly divided into seven groups (20 each): group 1, blank control group without any interference during the study; group 2, CCl4-induced liver fibrosis group; group 3, pig serum-induced liver fibrosis group; group 4, prophylaxis group of CCl4-induced liver fibrosis by Yi-gan-kang, group 5,prophylaxis group of pig serum-induced liver fibrosis by Yi-gan-kang, group 6, treatment group of CCl4-induced liver fibrosis by Yi-gan-kang, group 7, treatment group of CCl4-induced liver fibrosis by Yi-gan-kang. At wk 6, 10, 14 and 20(baseline for CCl4 or big serum induction), five rats in each group were anesthetized and their livers were removed for pathological studies including immunohistochemicalstudies for α-SMA, type Ⅰ collagen and in situ hybridization of tissue inhibitor of metalloproteinase-1 (TIMP-1) mRNA of hepatic stellate cells (HSCs). Anti-lipid peroxidation in isolated mitochondria and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) colorimetric assay for proliferation and terminal deoxynucleotidyl transferasemedicated dUTP-biotin nick end-labeling (TUNEL), flow cytometry and electron microscopy for apoptosis in isolated HSCs were also studied.RESULTS: The mean number of pseudolobuli at wk 10,14 and 20 in the prophylaxis group was significantly less than that in the control group (P＜0.05 or 0.01). The effectof prophylaxis at wk 14 in CCl4 rats and at wk 10 in pig serum-induced rats was much better than that of treatment group (P＜0.01). The thickness (in μm) of fibers both in pig serum-induced prophylaxis and in treatment groups at wk 14 and. 20 was significantly less than that in control group (P＜0.05). The number of fibers both in prophylaxis and in treatment groups from wk 10 or 14 to 20 was significantly less than that in control group (P＜0.05 or P＜0.01). The tissue HSC positive rates of type Ⅰ collagen, α-SMA and TIMP-1 mRNA, which represented the active phenotype of HSCs in tissues, remained very high from wk 6 to the end of model making in control group. While in prophylaxis group, they were at a relatively low level. In treatment group, there was a gradual decreasing trend. Time- and dose-dependent effects of anti-lipid peroxidation on isolated mitochondria, cell proliferation and apoptosis in cultured HSCs were also observed during the study.CONCLUSION: Yi-gan-kang can effectively inhibit or inverse the course of liver fibrogenesis in CCl4- and pig serum-induced rat models.