A rat model was developed to study intraperitoneal (ip) dialysis as a means of total nutritional support. Rats (200 g) were implanted ip with a catheter device and connected to a rodent infusion assembly. An automated system exchanged 10-ml volumes of a 37 degrees C solution containing 10% dextrose, 2% amino acid solution plus micronutrients. Rats were adapted over 3 days to a schedule of 16 1-hr cycles/day, and continued on this regimen for another 4 days. Rats subjected to this program maintained similar body weight, nitrogen balance, plasma chemistries, and liver tests in comparison to control animals fed per os in isocaloric and isonitrogenous amounts. Efficiency of peritoneal absorption for both glucose and amino acid was 95%. Histological examination of intraabdominal organs revealed only mild inflammation. This model is applicable to studies involving nutritional support via the peritoneal cavity, a technique which may be of value in patients with sensitive fluid balances (cardiac, renal, or pulmonary failure).