This experiment was aimed to discuss the protective effect and mechanism of total lignans from Tibetan medicinal Herpetospermum seeds on carbon tetrachloride (CCl4)-induced liver fibrosis in rats. Forty-eight male Sprague-Dawley rats were randomly divided into the blank control group (G1), model group (G2), total lignans high, middle and low dose groups (400,200, and 100 mg•kg⁻¹â€¢d⁻¹)(G3/4/5) and the glycyrrhizin positive control group (25 mg•kg⁻¹â€¢d⁻¹)(G6), n=8 in each group. The rats in blank group received normal feeding; the rats in model group, total lignans low, middle and high dose groups and glycyrrhizic group were subcutaneously in jected with 3 mL•kg⁻¹ olive oilsolution containing 40%CCl4 every two or three days for Eight weeks. During the course, the rats inblank group and model group were orally administered with 2 mL normal saline, and the rats in total lignans groups and the glycyrrhizin positive control group received corresponding doses of drugs by intragastric administration. Eight weeks later, after the the last time modeling, the rats were sacrificed. Then the biochemical analysis was used to determine alanine aminotransferase(ALT), aspartate aminotransferase(AST), and alkaline phosphatase (ALP) levels in serum while enzyme-linked immuno sorbent assay(ELISA) was applied for detecting transforming growth factor ß1(TGF-ß1), hyaluronic acid(HA), hydroxy-proline(HYP) and superoxide dismutase(SOD) levels in serum. HE and Masson's trichrome stainings were conducted in liver tissues to observe the pathological variations and grades of hepatic fibrosis. The results showed that as compared with the model group, the levels of ALT, AST, ALP, TGF-ß1, HA, HYP and SOD in serum of total lignans groups were significantly decreased (P<0.05, P<0.01); levels of SOD in the liver tissue homogenate were increased(P<0.05, P<0.01); the pathological damage of the liver tissues were relieved (P<0.05, P<0.01), and liver fibrosis scores were decreased(P<0.05, P<0.01). The above experimentsindicated that total lignans from Tibetan medicinal Herpetospermum seeds can effectively reduce carbon tetrachloride-induced hepatic injury of rat liver fibrosis, reduce the degree of liver fibrosis, and its mechanism maybe associated with down-regulating TGF-ß1 expression.