OBJECTIVES: Complications after colorectal surgery have not been reduced in recent years. Anastomotic leakage is responsible for nearly all morbidity in colonic surgery and for about one third of the mortality. MATERIAL AND METHODS: For the study, 34 albino Wistar rats (about 155-190 g in weight) were divided into four experimental groups. Each of the rats underwent an abdominal incision and resection of the colon 4 cm distal to the cecum to form a colo-colonic anastomosis. In the post-operative period, the first group (n=8) were fed with standard rat food and water, the second group (n=9) with dextrose+Ringer solution, the third group (n=9) with Biosorb® (Nutricia, Zoetermeer, The Netherlands), and the fourth group (n=8) with Impact® (Novartis Nutrition, USA). RESULTS: The blow-out pressure of the anastomoses was significantly different in the group fed 5% dextrose+Ringer solution group than in the Biosorb® and Impact® groups. CONCLUSIONS: None of the various nutrients investigated in the present study were significantly superior to standard foods in terms of the blow-out pressures. On the other hand, immunonutrients were more beneficial effects than other nutrients in terms of the healing of colonic anastomoses and post-operative weight loss. Advances in Clinical and Experimental Medicine 24(3):463-467 · May 2015