AIM: To establish the rats model of chronic fibrosing pancreatitis and to prove the anti-fibrotic effect of emodin in chronic pancreatitis with fi brosis. METHODS: Fifty rats were randomly divided into five groups, 10 rats in each group. Trinitrobenzene sulfonic acid (TNBS) was infused into the pancreatic duct to induce chronic pancreatitis in rats (except for normal group). Emodin-treated rats were fed with different doses of emodin (20, 40 and 80 mg/kg body weight) for 28 d, while normal group and control group received 0.9% sodium chloride solution. Serum levels of hyaluronic acid (HA) and laminin (LN) were determined by radioimmunoassay. Histopathological alterations were studied by optical microscopy. Expression of collagen was also examined while transforming growth factor-beta-1 (TGF-β1) was localized by immunochemistry. RESULTS: In emodin-treated rats, the serum levels of HA and LN were decreased significantly (HA, 62.2 ± 19.3 μg/L vs 112.7 ± 26.5 μg/L, P < 0.05; LN 44.3 ± 10.4 μg/L vs 86.2 ± 16.5 μg/L, P < 0.05); the degree of fibrosis was ameliorated observably; the expression of collagen in pancreatic tissue was reduced especially in high-dose emodin-treated group (36% ± 5% vs 42% ± 6%, P < 0.05); with the increased doses of emodin, the expression of TGF-β1 was declined, compared with those in control group. CONCLUSION: Emodin has an anti-fibrotic effect on pancreatic fibrosis in rats. Because of its anti-fibrotic effect, it could be a potential herb for the treatment of chronic pancreatitis. AIM: To establish the rats model of chronic fibrosing pancreatitis and to prove the anti-fibrotic effect of emodin in chronic pancreatitis with fi brosis. METHODS: Fifty rats were divided into five groups, 10 rats in each group. Trinitrobenzene sulfonic acid (TNBS ) was infused into the pancreatic duct to induce chronic pancreatitis in rats (except for normal group). Emodin-treated rats were fed with different doses of emodin (20, 40 and 80 mg / kg body weight) for 28 days while while group and control group received 0.9% sodium chloride solution. Serum levels of hyaluronic acid (HA) and laminin (LN) were determined by radioimmunoassay. Histopathological alterations were studied by optical microscopy. Expression of collagen was also found while transforming growth factor-beta-1 (TGF-β1) was localized by immunochemistry. RESULTS: In emodin-treated rats, the serum levels of HA and LN were significantly decreased (HA, 62.2 ± 19.3 μg / L vs 112.7 ± 26.5 μg / L, P < 44.3 The degree of fibrosis was ameliorated observably; the expression of collagen in pancreatic tissue was reduced especially in high-dose emodin-treated group (36% ± 5% vs 42% ± 6%, P <0.05); with the increased doses of emodin, the expression of TGF-β1 was declined, compared with those in control group. CONCLUSION: Emodin has an anti-fibrotic effect on pancreatic fibrosis in rats. Because of its anti-fibrotic effect, it could be a potential herb for the treatment of chronic pancreatitis.