The acute renal insufficiency (A.R.I.) consequent on surgical pathology of the aorta is in the Milan School, one of the most important postoperative complications and requires the use of total parenteral feeding (T.P.F.). Parenteral infusion of AAe and hypertonic glucose in patients with A.R.I. has given positive results, not only insofar as it improves the general nutritional state, but also because it facilitates recovery of renal function and improves survival. Reutilisation of endogenous nitrogen gives a synthesis of structural proteins to the benefit of metabolic homoeostasis and the patient's clinical condition. On the basis of recent nephrology studies on uraemic toxicity, the therapeutic problem of A.R.I. in surgical patients has been examined: early peritoneal dialysis associated with T.P.F. and the combination, in the postoperative stage, of parenteral feeding and periodic peritoneal dialysis. The average duration of this treatment has been personally found to be about 8-18 days. The example is given of a clinical case of A.R.I. in a patient operated by aneurysmectomy for rupture of an aneurysm of the abdominal aorta.