In patients with portal hypertension and tense ascites, large-volume paracentesis improves patient comfort and may improve systemic hemodynamics. However, it has been avoided in nonedematous patients because of concern for complications, including intravascular volume depletion. In this study, 12 nonedematous patients with chronic liver disease, portal hypertension and tense ascites underwent 14 large-volume (5-liter) paracenteses for the relief of discomfort and/or respiratory distress. Plasma volume was measured directly by a dilution method with 125I-labeled human serum albumin prior to and at 24 or 48 hr after 13 of the paracenteses. All patients felt better postparacentesis. No dizziness, hypotension, tachycardia, encephalopathy or change in mean serum sodium, creatinine or blood urea nitrogen occurred. Two patients experienced a decrease in hematocrit, which was not explained by blood loss or increase in plasma volume. Mean plasma volume was 3,713 +/- 129 ml (55.1 +/- 1.5 ml per kg ideal body weight) preparacentesis and 3,684 +/- 136 ml postparacentesis, the difference being -0.78% (p = 0.48, NS). Our results suggest that 5-liter paracentesis in nonedematous patients with tense portal hypertension-related ascites improves patient comfort and is not associated with a decrease in measured plasma volume.