Hepatitis C virus (HCV) has been proposed to be a cofactor in the pathogenesis of cirrhosis in patients with chronic alcoholism. The demonstration of a different liver histological pattern in anti-HCV positive patients might provide additional evidence. We studied 164 patients with chronic alcoholism, and histologically proven cirrhosis. For all of them, serum samples were collected at the time of a liver biopsy and stored at -80 degrees C. Testing for anti-HCV antibodies was done using the Ortho Diagnostic Systems Anti-HCV ELISA test. Only reproducible results were considered positive. A semi-quantitative assessment of seven histological parameters was made independently on liver biopsy samples. In the study group, 29 patients (18%) had anti-HCV antibodies. When compared with anti-HCV negative patients, both groups had similar ALT and AST seric activities. Anti-HCV positive patients had a greater score of mononuclear cells infiltrate (0.71 +/- 0.57 vs 0.41 +/- 0.52; p less than 0.05) and a lesser score of alcoholic hepatitis (0.19 +/- 0.57 vs 0.74 +/- 0.74; p less than 0.005). The scores for steatosis, perisinusoidal and perinodular fibrosis, and hepatocellular necrosis were similar in the two groups. In anti-HCV positive patients, with a clearly positive recombinant immunobinding assay (RIBA, Chiron-Ortho Diagnostic Systems), a greater score for hepatic necrosis and a lesser one for fibrosis were demonstrated. Among the seven patients with active cirrhosis, six were anti-HCV positive. Therefore, HCV is likely to play a role in the pathogenesis of liver damage in a few patients with alcoholic cirrhosis, especially, those with active cirrhosis.