Serum levels of fasting glycocholic acid were measured in various noncirrhotic liver diseases. Forty-five patients were evaluated, 15 with chronic active hepatitis and 30 with mild liver diseases including chronic persistent hepatitis, steatosis, and minimal changes. There were increased levels of glycocholic acid in 53.3% of chronic active hepatitis cases and in 10% of mile liver disease cases (P = 0.003), and the levels reached by patients with chronic active hepatitis were higher than those in patients with mild liver disease (P < 0.0001). The latter did not show significant differences in their serum levels or in the percentage of abnormal results with respect to control group. There were weak, although significant, correlations between glycocholic acid and transaminases, alkaline phosphatase, gamma-glutamyltranspeptidase, albumin, and gammaglobulin. In the present study, the specificity of glycocholic acid was high in the detection of chronic active hepatitis patients at different cut-off levels. Glycocholic acid appeared to reflect histological severity in this group of noncirrhotic liver diseases and might have practical applications in the management of these patients.