The plasma clearance of a tracer dose of 14C-glycocholic acid, and fasting total serum bile acid concentrations were measured in 14 control subjects and in 38 patients with acute and chronic liver disease. In controls plasma clearance was 415 +/- 24 ml min-1 m-2 (mean +/- SEM), equivalent to a 'first-pass' extraction by the liver of 85%. Clearance was not significantly different from controls in patients with acute hepatitis or active chronic hepatitis, nor in anicteric patients with primary biliary or alcoholic cirrhosis. Thus bile acid clearance was impaired only in icteric chronic liver disease. In contrast, serum bile acid concentrations were abnormal in all but seven patients, six of whom had active chronic hepatitis in complete biochemical remission. The pattern of plasma disappearance of injected 14C-glycocholic acid was biexponential in controls and patients with liver disease, and computer analysis of the curves suggested that there was significant distribution of bile acid outside the vascular space. The preservation of bile acid clearance in anicteric chronic liver disease confirms that it is dependent more on liver blood flow than on liver cell function.