We compared total body water and intracellular-extracellular distribution of body water between male patients with mild liver disease without ascites (n = 9), male patients with severe liver disease and gross ascites (n = 6) and a group of age-, sex-, height- and weight- matched controls (n = 6). In addition, we documented the effects of liver transplantation on intracellular, extracellular and total body water in 12 patients (6 men and 6 women) by means of deuterium oxide dilution and whole-body potassium counting. We saw no significant difference in total body water between the healthy controls, patients without ascites and patients with ascites (46.5 +/- 9.2 kg, 45.4 +/- 6.6 kg and 50.4 +/- 5.1 kg, respectively), although, as expected, extracellular water was increased in patients with ascites compared with healthy controls and cirrhotic patients without ascites (36.9 +/- 6.5 kg vs. 25.4 +/- 4.4 kg, p = 0.005; and 36.9 +/- 6.5 kg vs. 27.0 +/- 5.3 kg, p = 0.002, respectively). We found no difference between non-ascitic patients and healthy controls (25.4 +/- 4.4 kg vs. 27.0 +/- 5.3 kg). However, intracellular water was significantly reduced in patients with severe liver disease compared with that in controls (13.6 +/- 3.3 kg vs. 21.5 +/- 4.2 kg, p = 0.005) or patients without ascites (13.6 +/- 3.3 kg vs. 18.3 +/- 2.9 kg, p = 0.01). The reduction of intracellular water appears to be due to loss of body cell mass.(ABSTRACT TRUNCATED AT 250 WORDS)