AIM: To investigate whether antioxidants vitamin E and C can retard development of hepatic fibrosis in the bili- ary-obstructed rats. METHODS: Fifty Wistar albino rats were randomly as- signed to 5 groups (10 rats in each). Bile duct was liga- ted in 40 rats and they were treated as follows: group vitC, vitamin C 10 mg/kg sc daily; group vitE, vitamin E 15 mg/kg sc daily; group vitEC, both of the vitamins; bile duct-ligated (BDL, control) group, physiological saline sc. The fifth group was assigned to sham operation. At the end of fourth week, the rats were decapitated, and hepatic tissue biochemical collagen content and collagen surface area were measured. Hepatic tissue specimens were histopathologically evaluated according to Scheuer system. Serum hyaluronate levels were measured by ELISA method. RESULTS: Despite being higher than sham group, he- patic collagen level was significantly decreased in each of the vitC, vitE and vitEC groups (32.7 ± 1.2, 33.8 ± 2.9, 36.7 ± 0.5 μg collagen/mg protein, respectively) compared to BDL (48.3 ± 0.6 mg collagen/g protein) (P < 0.001 for each vitamin group). Each isolated vitamin C, isolated vitamin E and combined vitamin E/C supp-lementation prevented the increase in hepatic collagen surface density (7.0% ± 1.1%, 6.2% ± 1.7%, 12.3% ± 2.0%, respectively) compared to BDL (17.4% ± 5.6%) (P < 0.05 for each). The same beneficial effect of vitamin C, vitamin E and combined vitamin E/C treatment was also observed on the decrease of serum hyaluronate levels compared to BDL group (P < 0.001). The relative liver and spleen weights, serum transaminases, cholestatic enzymes, bilirubins and histopathological inflammation scores were not different between the antioxidant treat- ment groups and the control. However, fibrosis staging scores were obviously reduced only in the vitamin E/C combination group (vit EC: 2.4 ± 0.8 vs BDL: 3.1 ± 0.7; P < 0.05). CONCLUSION: Each antioxidant vitamin E, vitamin C and their combination retard hepatic fibrosis in biliary-obs- tructed rats. Oxidative stress may play a role in the patho- genesis of hepatic fibrosis in secondary biliary cirrhosis. AIM: To investigate whether antioxidants vitamin E and C can retard development of hepatic fibrosis in the bili- ary-obstructed rats. METHODS: Fifty Wistar albino rats were randomly as- signed to 5 groups (10 rats in each). Bile duct was liga group ted in 40 rats and they were treated as follows: group vitC, vitamin C 10 mg / kg sc daily; group vitE, vitamin E 15 mg / kg sc daily; group vitEC, both of the vitamins; bile duct- ligated The fifth group was assigned to sham operation. At the end of fourth week, the rats were decapitated, and hepatic tissue biochemical collagen content and collagen surface area were measured. Hepatic tissue specimens were histopathologically evaluated to Scheuer system. Serum hyaluronate levels were measured by ELISA method. RESULTS: Despite being higher than sham group, he- patic collagen level was significantly decreased in each of the vitC, vitE and vitEC groups (32.7 ± 1.2, 33.8 ± 2.9, 36.7 ± 0.5 μg col lactic / mg protein, respectively) compared to BDL (48.3 ± 0.6 mg collagen / g protein) (P <0.001 for each vitamin group). Each isolated vitamin C, isolated vitamin E and combined vitamin E / C supp-lementation prevented the increase in hepatic collagen surface density (7.0% ± 1.1%, 6.2% ± 1.7%, 12.3% ± 2.0%, respectively) compared to BDL (17.4% ± 5.6% C, vitamin E and combined vitamin E / C treatment was also observed on the decrease of serum hyaluronate levels compared to BDL group (P <0.001). The relative liver and spleen weights, serum transaminases, cholestatic enzymes, bilirubins and histopathological inflammation scores were However, fibrosis staging scores were significantly reduced in the vitamin E / C combination group (vit EC: 2.4 ± 0.8 vs BDL: 3.1 ± 0.7; P <0.05). CONCLUSION : Each antioxidant vitamin E, vitamin C and their combination retard hepatic fibrosis in biliary-obs-tructed rats. Oxidative stress may play a role in the patho- genesis of hepatic fibrosis in secondary biliary cirrhosis.