&NA;The comparative role of free ometal, peritoneal, Dacron®velour, and Marlex®mesh grafts in reinforcement of an extremely vulnerable experimental model of large‐bowel anastomosis was studied in dogs. While both the omentum and peritoneum proved not to be effective in preventing anastomotic leakage, Dacron velour did considerably lower this incidence to within reasonable limits but led to formation of low‐grade lymphoma at the reinforcement site in two animals. Only Marlex mesh was found to be highly effective in sealing the suture line, and it is anticipated that, with the usual teachnique of anastomosis, this sealing effect will be foolproof, thereby nullifying any risk of suture‐line breakdown