We studied 35 cirrhotic patients with tense ascites assigned at random into two groups: Group I consisted of 17 patients treated by total therapeutic paracentesis (TTP) (6-15 l) plus i.v. albumin (5 g/l of fluid) and Group II consisted of 18 patients treated by TTP (5.5-15.5 l) without albumin. On 19 patients we performed a sequential assessment of cardiac output (CO), plasma renin activity (PRA) and plasma aldosterone (PA). Both groups were similar in age, sex, and etiology of cirrhosis. CO, PRA and PA values were expressed as mean changes occurring in relation to their respective baseline values. CO changes after TTP (l/min): Group I: 2.5 after 6 h and 2.2 after 12 h; Group II: 2.2 after 6 h and -0.4 after 12 h, (p < 0.05 comparing values after 12 h between the two groups). PRA changes after TTP (ng/dl/h): Group I: -7.4 after 1 h, -7.8 after 6 h and -3.2 after 24 h; Group II: -2.4 after 1 h, -0.8 after 6 h and 3.9 after 24 h (p < 0.05 comparing values between both groups after 6 and 24 h). PA changes after TTP (ng/dl): Group I: -50.5 after 1 h, -36.7 after 6 h and -34.6 after 24 h; Group II: -18.2 after 1 h, -2.2 after 6 h and 20 after 24 h, (p < 0.05 comparing values between both groups after 1 and 6 h). Complications were minimal in both groups.(ABSTRACT TRUNCATED AT 250 WORDS)