In search of an effective agent for decreasing intravariceal pressure, 27 patients with portal hypertension and large esophageal varices were studied. Thirteen patients received iv nitroglycerin (150-micrograms bolus), and 14 received iv metoclopramide (20-mg bolus). Continuous measurement of variceal pressure and systemic hemodynamics was carried out. Compared with the baseline, the variceal pressure was significantly reduced 10 min after nitroglycerin injection (20.23 +/- 3.1 vs. 14.6 +/- 4.8 mm Hg, p < 0.05): the percentage reduction was 27 +/- 25.4%. With metoclopramide, variceal pressure decreased by 12.7 +/- 22%; from 21.9 +/- 5.6 to 19.1 +/- 7.7 mmHg (p = NS). There was no significant alteration in the heart rate and mean arterial pressure with either drug. Our results thus suggest that in the dosages used, intravenous nitroglycerin effectively and safely reduces the variceal pressure. Further studies using a combination of nitroglycerin and metoclopramide need to be considered.