The effect of decreased colloid oncotic pressure, as seen in hypoalbuminemia and hypoproteinemia, upon intestinal function has been well delineated in the surgical literature. Patients undergoing abdominal aortic aneurysm resection or aortoiliac or aortofemoral bypass grafts are almost uniformly hypoalbuminemic postoperatively; with these two facts in mind, a prospective, randomized clinical study was undertaken to identify the role of serum albumin concentration on the length of postoperative ileus in this population. The main hypothesis was that patients whose albumin levels dropped below 3.5 gm/dL would have a more prolonged postoperative hospital course as a result of delay in return of bowel function when compared with those patients in whom the low albumin levels were exogenously acutely replenished to > 3.5 gm/dL. Albumin was replaced to a level greater-than or equal to 3.5 g/dL in one group of 37 patients (AR), with a control group of 32 patients (NR) not receiving any albumin. Return of bowel function was measured by the postoperative day that flatus was documented, as well as the postoperative day oral intake was resumed. Mean values were determined for each group, and t tests did not reveal a significant difference in postoperative day of flatus (AR mean = 4.06 days, NR mean = 4.16 days) or postoperative day of oral intake (AR mean = 4.0, NR mean = 3.75). Additional comparisons between the groups involving the number of postoperative days until a regular diet was begun (AR mean = 6.06, NR mean = 5.48) and length of postoperative hospital stay (AR mean = 9.16, NR mean = 8.43) failed to reveal significant differences.(ABSTRACT TRUNCATED AT 250 WORDS)