1. The effect of intravenous fenoldopam-an arterial vasodilator-was assessed in twelve patients with cirrhosis and portal hypertension. Six patients had compensated (Grade A or B Child-Pugh classification) and six decompensated (Grade C) liver disease. 2. A significant dose dependent reduction in systemic blood pressure with a concomitant fall in systemic vascular resistance and increase in cardiac index was observed. Estimated portal pressure (WHVP-FHVP) increased (15.4 +/- 3.2 to 19.3 +/- 3.7 mm Hg, P less than 0.05) due to a rise in wedged hepatic venous pressure (24.6 +/- 4.3 to 29.0 +/- 5.8 mm Hg, P less than 0.05). Hepatic blood flow did not change significantly. Similar haemodynamic effects were observed in both compensated and decompensated patients. 3. Fenoldopam plasma clearance and ICG clearance were found to decrease with increasing infusion concentration, indicating possible increase of the intrahepatic shunting. 4. With the observed rise in portal pressure there must be some concern with respect to the long-term use of this drug in patients with previous variceal bleeding.