Eleven patients with ascitic cirrhosis and eleven patients without liver disease received 200 mg of cimetidine orally and intravenously. Plasma concentrations of cimetidine were analysed by high pressure liquid chromatography. No differences were observed in cimetidine half-life (2.53 +/- 0.63 and 2.33 +/- 0.40 h) between the two groups. Cimetidine clearance was diminished by about 30 p 100 in cirrhotic patients (0.426 +/- 0.138 vs. 0.649 +/- 0.163 l/h/kg). The apparent volume of distribution was also significantly diminished (1.50 +/- 0.44 vs. 2.14 +/- 0.55 l/kg) in patients with cirrhosis and ascites.