AbstractIntroductionClosed loop obstruction is commonly encountered in sigmoid volvulus. When such obstruction becomes fulminant, it is called acute necrotizing colitis. Gangrene of the entire large bowel from the caecum till the distal end of the sigmoid is a rare entity.Presentation of the caseWe present here one such case of necrotizing colitis in a 27 years old gentleman who presented with large bowel obstruction and septic shock. Computed tomography (CT) revealed sigmoid volvulus with ischaemic changes. The rest of the colon was dilated. On laparotomy, a gangrenous sigmoid due to the volvulus was found along with complete gangrene of the proximal bowel from the ileocaecal junction till the volvulus. This was probably due to a double cl...