A 73-year-old woman with chronic constipation and associated megarectum and megacolon presented as an emergency with colonic perforation, inferior vena caval obstruction and urinary retention. Soon after admission the patient sustained a massive feculent vomit and died. Intractable constipation demands referral for further investigation, if similarly neglected cases are to be avoided. Idiopathic megacolon presenting in this way has not been previously reported.