PURPOSE:This study was designed to investigate the protective effect of a pedunculated seromuscular flap on intestinal anastomosis after corticosteroid treatment.METHODS:Forty male Sprague‐Dawley rats were divided into four groups, and all animals underwent intestinal anastomosis. Two groups, with or without seromuscular flap wrapping, received 5 mg cortisone acetate, and two groups received placebo (saline) preoperatively for 16 days. Anastomotic strength was defined as bursting pressure (in millimeters of mercury). The pedunculated seromuscular flap was prepared from a segment of intestine next to the anastomosis. Intestinal bursting strength at the anastomotic site was measured at Postoperative Day 8.RESULTS:The anastomotic bursting strength was significantly lower in the steroid groups at Postoperative Day 8 (P<0.01). The pedunculated seromuscular flap increased the strength of the anastomosis both in the steroid and control groups (P<0.05).CONCLUSION:The adverse effect of corticosteroids on intestinal anastomoses may be prevented by a pedunculated seromuscular flap.