Ten patients with cirrhosis and protal hypertension received an initial 20 mg oral test dose of propranolol and subsequently 160 mg of a slow release preparation, orally, each day for seven days. Protein binding, serial plasma propranolol concentrations and effects on heart rate were studied. Protein binding was slightly reduced (mean 85%, range 78.9-88.1%) compared with four normals (mean 87.9%). In patients with severe liver disease (serum albumin less than 30 g/l) propranolol remained detectable in plasma 24 hours after the single 20 mg dose and high steady state concentrations (mean 266.5 ng/ml, range 84-406) were observed during regular dosing. At steady state there was a significant correlation between log total plasma propranolol concentrations and the percentage fall in heart rate (r = 0.659, p less than 0.05). We suggest that in patients with severe liver chronic disease (serum albumin less than 30 g/l), propranolol therapy should be initiated in hospital. The starting dose should be low (20 mg of the conventional formulation tds or 80 mg of the slow release preparation daily) and that regular monitoring of the heart rate should be carried out.