The hemodynamic effects of long-term (3 months) treatment with enalapril, a potent angiotensin converting enzyme inhibitor, were studied in 12 randomly selected patients with portal hypertension and a previous episode of hemorrhage from esophageal varices. All these patients underwent injection sclerotherapy of varices at 1-week intervals. As a control group 13 patients treated only with injection sclerotherapy and placebo were used. After 3 months the wedged hepatic venous pressure (25.5 +/- 4.8 vs. 21.3 +/- 4.8 mmHg) and the non-wedged hepatic venous pressure gradient (17.0 +/- 6.0 vs. 12.6 +/- 3.4 mmHg) were significantly lower than the basal values (p < 0.01) in the group treated with enalapril. A large decrease (> 3 mmHg) in these pressures was observed only in 50% of the patients. In the group treated with sclerotherapy+placebo this pressure reduction was not observed. Systemic hemodynamics and liver function tests did not change during the treatment. None of our patients died during the study or the next 6 months. We conclude that enalapril lowers portal pressure in patients with portal hypertension, although not in all of them, and may be used to good effect to manage patients with esophageal varices in combination with sclerotherapy.