A new method for concentrated ascitic fluid reinfusion using a double ultrafiltration device is reported as 22 procedures in 20 cirrhotic patients (6 females, 14 males; median age 55 years, range 33-69) with tense, refractory ascites. Eight of the 20 patients had elevated creatinine levels. The mean time for each procedure was 189 +/- 82 min, during which a mean of 7.7 liters (1.3-13.3) of ultrafiltered ascitic fluid was removed and 613 ml (140-1700) of concentrated ascitic fluid rich in albumin (mean: 60 g, range 14-175) was reinfused. The procedure resulted in a mean weight loss of 8.1 kg (2.2-14.0) and a mean increase of 163 ml in urine output (24 hr). A reduction in the serum creatinine level (P < 0.05) and an increase in the plasma atrial natriuretic factor level (P < 0.02) 24 hr after reinfusion, while no changes in serum albumin, plasma and urinary electrolytes, plasma renin activity, aldosterone, and antidiuretic hormone levels were noted. Although minor evidence for a disturbance in coagulation was observed, there were no episodes of clinical bleeding. Four patients (20%) had transient chills or fever. Based upon this experience, it can be concluded that reinfusion of cascade filtered and concentrated ascitic fluid is a rapid, safe, and effective treatment for patients with tense ascites; it appears to have less side effects than more traditional methods and importantly does not require administration of heterologous plasma derivatives.