The clearance, half-life time, fractional elimination rate and distribution volume of indocyanine green (10 mg . m-2) were measured in 20 control subjects and 63 patients with histologically confirmed liver disease. Mean clearance was significantly impaired only in the patients with alcoholic and primary biliary cirrhosis; in those with active chronic hepatitis, with or without cirrhosis, or with acute hepatitis, clearance was normal. However, half-life time and fractional elimination rate were impaired in all but one group of patients. This discrepancy arose because of a significantly increased distribution volume in all groups with chronic liver diseases except primary biliary cirrhosis. Thus, in chronic liver disease, half-life times and fractional elimination rates do not necessarily reflect hepatic uptake; measurement of clearance is therefore to be preferred.