A 79-year-old male was transferred to the intensive care unit for postoperative respiratory support. An indwelling bowel management system was inserted for containment of noninfective diarrhoea. Following only 11 days of continual use the patient developed life-threatening rectal bleeding. Preoperative normal rectal mucosa and anatomy were documented. There was no evidence of postoperative coagulopathy. Mesenteric angiography identified bleeding from a branch of the superior rectal artery. Rectal mucosa pressure necrosis secondary to the indwelling Flexi-Seal® Fecal Management System was diagnosed. The patient required an 11-unit transfusion of packed red cells. Following intraarterial coil embolization of the superior rectal artery the bleeding abated. Indwelling bowel management systems are commonly used in immobile and critically ill patients with diarrhoea or faecal incontinence. This is the first report of this important complication in the literature.