Constipation in patients with advanced cancer results from reduced food intake and debility as well as medication, particularly opioid analgesics. Prophylactic measures are important, but most patients will require laxatives. History and examination should exclude the presence of intestinal obstruction, and if there is doubt, only a softening laxative should be used. In general, a combination of softening and stimulant laxatives is most likely to be successful with minimum adverse effects. Management of constipation is frequently poor, and considerable research effort is needed into both the more effective use of current treatments and the development of new therapies.