The successful management of constipation depends on defining the patient's symptoms, excluding secondary causes, and characterizing the abnormality of defecation. Constipation without gut dilatation is found commonly in pregnancy, the elderly, and those with the irritable bowel syndrome. In addition, there is a group of patients that has intractable, severe idiopathic constipation. Some have ‘slow transit’ and open their bowels every 1–4 weeks. Others have a defecatory disorder with normal colonic transit. Constipation with gut dilatation is seen in Hirschsprung's disease, idiopathic megarectum and megacolon, chronic intestinal pseudo-obstruction and Chagas' disease. Constipation can also result from disturbance to the autonomic outflow of the gastrointestinal tract, and colonic function may be also affected by psychological factors. This review article discusses the presentation, investigation and management of patients with constipation.