A survey of all patients in whom liver biopsy showed epithelioid granulomas was undertaken at two major teaching hospitals in Glasgow for the period 1970-1979. Seventy-seven patients with hepatic granulomas were studied retrospectively. In 53 cases (69 per cent) a clear-cut clinical diagnosis was established, which included sarcoidosis (eight cases), tuberculosis (eight), extrahepatic biliary obstruction (seven), primary liver diseases (11), neoplasm (six), bacterial infection (five) and miscellaneous (eight). In 24 patients (31 percent) no cause was found. Seventeen patients from this idiopathic group were studied prospectively and single examples of the following conditions were subsequently diagnosed; pulmonary tuberculosis, primary biliary cirrhosis, ulcerative colitis, adenocarcinoma of rectum, primary hepatocellular carcinoma, alpha-one antitrypsin deficiency and pulmonary fibrosis, sarcoidosis, pulmonary fibrosis alone, gallstones, rheumatic heart disease, unexplained hepatosplenomegaly and one death from mesenteric artery thrombosis. Only six cases remained truly idiopathic. Three of these patients recovered and in two liver biopsy became normal. The other three have persistent granulomas associated with continuing illness.