[Objective] To reveal the anti-hepatic fibrosis action of Perfoliate Knotweed Herb against N-Nitrosodimethylamine-induced rat model and its mechanism. [Method] Eighty SD rats were randomly divided into 6 groups: normal group,model group,Perfoliate Knotweed Herb medication groups(high,medium and low doses) and colchicine group. Except normal group,rats in all other groups were medicated by introperitoneal injection with 0. 5% DMN solution (1. 6 mL/kg) for continuous 3 d within a week. First week used 2 /3 dose and then full dose was adopted. colchicine medication group adopted 0. 1 mg/kg colchicine; high,medium and low doses of Perfoliate Knotweed Herb medication groups applied 7. 5,5. 0 and 2. 5 g/kg. Medication was performed once a day and continued for 4 weeks. At the end of 4th week,blood collected from eyeball execution was used for detection of serum hyaluronic acid (HA) ,Laminin(LN) ,precollagen III (PCIII) ,collagen IV (IV-C) by using ELISA. HF formation was observed by hematoxylin-eosin stain(HE stain) ; immunohistochemical assay was employed to detect the transformation growth factor β1 (TGF-β1) . [Results]In comparison with model group,serum HA,LN,PCIII and IV-C expression levels in high and medium dose Perfoliate Knotweed Herb medication groups were significantly lowered (P < 0. 05 or P < 0. 01) ; immunohistochemical assay indicated that TGF-β 1 level in high and medium dose groups were remarkably lowered (P < 0. 05 or P < 0. 01) ,while that in low dose group did not (P > 0. 05) . [Conclusion] Perfoliate Knotweed Herb is endowed with good efficacy on the treatment of N-Nitrosodimethylamine-induced hepatic fibrosis in rats,with the mechanism of down-regulating the expression of TGF-β1 ,thus inhibition the initiation of hepatic fibrosis. [Objective] To reveal the anti-hepatic fibrosis action of Perfoliate Knotweed Herb against N-Nitrosodimethylamine-induced rat model and its mechanism. [Method] Eighty SD rats were randomly divided into 6 groups: normal group, model group, Perfoliate Knotweed Herb groups (high, medium and low doses) and colchicine group. Except normal group, rats in all other groups were medicated by introperitoneal injection with 0.5% DMN solution (1.6 mL / kg) for continuous 3 d within a week. First week used 2/3 dose and then full dose was adopted. Colchicine medication group administered 0. 1 mg / kg colchicine; high, medium and low doses of Perfoliate Knotweed Herb drug groups applied 7. 5,5. 0 and 2.5 At the end of 4th week, blood collected from eyeball execution was used for detection of serum hyaluronic acid (HA), Laminin (LN), precollagen III (PCIII) , collagen IV (IV-C) by using ELISA. HF formation was observed by hematoxy [Results] In comparison with model group, serum HA, LN, PCIII and IV-C expression levels in high and (P <0.05 or P <0.01); immunohistochemical assay indicated that TGF-β 1 level in high and medium dose groups were remarkably lowered (P <0.05 or P <0. 01), while that in low dose group did not (P> 0.05). [Conclusion] Perfoliate Knotweed Herb is endowed with good efficacy on the treatment of N-Nitrosodimethylamine-induced hepatic fibrosis in rats, with the mechanism of down-regulating the expression of TGF-β1 thus inhibition the initiation of hepatic fibrosis.