Acute colonic pseudo-obstruction is the clinical syndrome of acute large bowel dilatation without mechanical obstruction that is an important cause of morbidity and mortality. Acute colonic pseudo-obstruction occurs in hospitalized or institutionalized patients with serious underlying medical and surgical conditions. The pathogenesis of acute colonic pseudo-obstruction is not completely understood but likely results from an imbalance in the autonomic regulation of colonic motor function. Metabolic or pharmacological factors, as well as spinal or retroperitoneal trauma, may alter the autonomic regulation of colonic function, leading to excessive parasympathetic suppression or sympathetic stimulation. This imbalance results in colonic atony and dilatation. Early recognition and appropriate management are critical to minimizing morbidity and mortality. The mortality rate is estimated at 40% when ischaemia or perforation occurs. The best-studied treatment of acute colonic pseudo-obstruction is intravenous neostigmine, which leads to prompt colon decompression in the majority of patients after a single infusion. In patients failing or having contraindications to neostigmine, colonoscopic decompression is the active intervention of choice. Surgery is reserved for those with peritonitis or perforation.