AIM: To evaluate the safety and efficacy of chronic administration of losartan on hepatic fibrosis in chronic hepatitis C patients. METHODS: Fourteen patients with chronic hepatitis C non-responders (n = 10), with contraindications (n = 2) or lack of compliance (n = 2) to interferon plus ribavirin therapy and liver fibrosis were enrolled. Liver and renal function test, clinical evaluation, and liver biopsies were performed at baseline and after losartan administration at a dose of 50 mg/d during the 6 mo. The control group composed of nine patients with the same inclusion criteria and paired liver biopsies (interval 6-14 mo). Histological activity index (HAI) with fibrosis stage was assessed under blind conditions by means of Ishak’s score. Subendothelial fibrosis was evaluated by digital image analyses. RESULTS: The changes in the fibrosis stage were significantly different between losartan group (decrease of 0.5±1.3) and controls (increase of 0.89±1.27; P<0.03). In the treated patients, a decrease in fibrosis stage was observed in 7/14 patients vs 1/9 control patients (P<0.04). A decrease in sub-endothelial fibrosis was observed in the losartan group. No differences were found in HAI after losartan administration. Acute and chronic decreases in systolic arterial pressures (P<0.05) were observed after the losartan administration, without changes in mean arterial pressure or renal function. CONCLUSION: Chronic AT-Ⅱ type 1 receptor (AT1R) blockade may reduce liver fibrosis in patients with chronic hepatitis C. METHODS: Fourteen patients with chronic hepatitis C non-responders (n = 10), with contraindications (n ​​= 2) or lack of compliance (n = 2) to interferon plus ribavirin therapy and liver fibrosis were enrolled. Liver and renal function test, clinical evaluation, and liver biopsies were performed at baseline and after losartan administration at a dose of 50 mg / d during the 6 mo. control group composed of nine patients with the same inclusion criteria and paired liver biopsies (interval 6-14 mo). Histological activity index (HAI) with fibrosis stage was assessed under blind conditions by means of Ishak’s score. Subendothelial fibrosis was evaluated by digital image RESULTS: The changes in the fibrosis stage were significantly different between losartan groups (decrease of 0.5 ± 1.3) and controls (increase of 0.89 ± 1.27; P <0.03). In the treated pati a decrease in fibrosis stage was observed in 7/14 patients vs 1/9 control patients (P <0.04). A decrease in sub-endothelial fibrosis was observed in the losartan group. No differences were found in HAI after losartan administration. Acute and chronic decreases in systolic arterial pressures (P <0.05) were observed after the losartan administration, without changes in mean arterial pressure or renal function. CONCLUSION: Chronic AT-II type 1 receptor (AT1R) blockade may reduce liver fibrosis in patients with chronic hepatitis C