This case report describes an eight-year-old girl who was admitted under the suspicion of gastroenteritis. The physical examination revealed symptoms of acute bowel obstruction, which was confirmed by abdominal CT scan. Explorative laparotomy showed a fibrotic membrane encapsulating the small intestine causing obstruction and ischaemia, and the perioperative diagnosis was abdominal cocoon syndrome. Two metres of the small intestine, excessive peritoneal membrane and the appendix was resected and an ileostomy was performed. The patient recovered with antibiotics, fluid therapy and parenteral nutrition.