The aim of this study was to investigate the hemodynamic effects of spironolactone associated with a low-sodium diet (n = 14) or a low-sodium diet alone (n = 9) in patients with compensated cirrhosis and portal hypertension. Spironolactone significantly reduced the plasma volume. This effect was associated with a significant reduction in the hepatic venous pressure gradient, from 17.6 +/- 3.6 mm Hg to 15.3 +/- 3.5 mm Hg (-13% +/- 13%; p < 0.01). Azygos blood flow (-20% +/- 20%), cardiac output (-16.2% +/- 10.5%) and mean arterial pressure (-9% +/- 9%) also decreased significantly. However, there were no significant changes in hepatic blood flow. Patients receiving low-sodium diet alone experienced a mild but significant reduction in hepatic venous pressure gradient (-6.3% +/- 6%) and in mean arterial pressure (-4% +/- 5%). There were no significant changes in cardiac output and in hepatic or azygos blood flows. This study indicates that low-sodium diet plus administration of spironolactone reduces portal pressure and azygos blood flow in patients with compensated cirrhosis. Low-sodium diet alone only produces mild effects that are likely to be clinically irrelevant.