Objective: To study the effect of the total flavonoids of Bidens bipinnata (TFB) on the TGF-β1/smad pathway of liver tissue in rats with liver fibrosis. Method: Liver fibrosis in rats was established by CCl4

and then the rats were randomly divided into five groups:model group

colchicine group (0.2 mg·kg-1)

low-

medium-and high-dosage groups of TFB (60

120

240 mg·kg-1)

as well as the normal group was set up. The drugs were given to rats daily for 30 consecutive days. The activities of alanine aminotransferase (ALT)

aspartate aminotransferase (AST) and total bilirubin (TBil) in serum were examined

and the levels of hyaluronic acid (HA)

laminin (LN)

precollagen III (PCIII) and hydroxyproline (Hyp) in hepatic tissue were examined. The transforming growth factor-β1(TGF-β1)-immunoreactive cells were determined by immunohistochemical assay

and the expression of smad2 and smad3 in hepatic tissue was determined by Western blot. In addition

the hepatic pathological changes were observed by Masson staining. Result: Compared with model group

TFB effectively decreased the activities of AST

ALT and TBil in rats with liver fibrosis (P<0.01)

the contents of HA

LN

PCIII and Hyp in homogenate were decreased (P<0.01). The quantity of TGF-β1-immunoreactive cells was reduced (P<0.01). The smad2 and smad3 protein level was down-regulated in hepatic tissue (P<0.01). Moreover

liver fibrosis was alleviated. Conclusion: TFB has protective effect on the CCl4-induced liver fibrosis in rats

the mechanism may be implicated in regulating the TGF-β1/smad pathway to inhibit collagenation.