Paracentesis associated with albumin administration has been shown to be a safe and useful procedure in the treatment of patients with cirrhosis and ascites. Given the high cost of albumin, 20 patients with cirrhosis and ascites were treated in an open study, with daily paracentesis using dextran 70, an inexpensive volume expander, instead of albumin. In the first 10 patients, hemodynamic evaluation was performed in basal conditions, after each paracentesis (5 liter), and after dextran infusion. Twelve hours after each paracentesis without expansion, a significant drop in pulmonary capillary wedge pressure from 9.5 +/- 1.0 to 7.1 +/- 1.7 (P < 0.01) and a reduction in cardiac output from 6.6 +/- 1.0 to 5.0 +/- 1.9 (NS) were observed. Moreover, the hematocrit rose significantly from 36.8 +/- 5.6 to 39.2 +/- 4.8 (P < 0.01). These parameters returned to baseline values after the administration of 84 +/- 14 ml of dextran 70 for each 1000 ml of ascites removed. The other 10 patients received dextran 70 simultaneously with the paracentesis without hemodynamic control. No significant changes in renal and hepatic functions were observed at the end of the study. The mean volume of ascites removed was 12.3 +/- 4.6 liter. Two patients developed hyponatremia that required no treatment. No patient developed renal failure. One patient died because of gastrointestinal bleeding. Our study shows: (1) large paracentesis without volume expansion produces hemodynamic and humoral changes compatible with reduction of intravascular volume; (2) the administration of 100 ml of dextran 70 for each 1000 ml of ascites removed avoids these hypovolemic changes; and (3) the use of dextran 70 allows a 30-fold reduction in cost compared with albumin.