Constipated patients who are refractory to simple lifestyle interventions will usually resort to laxatives, whether prescribed or over the counter. Clinical trial evidence is scarce for older medications such as laxatives, especially with a condition as chronic and subjective as constipation. Newer polyethylene glycol-based laxatives have been investigated under rigorous clinical trial settings, but comparisons between different laxatives are not available. Newer prokinetic agents, targeting peristalsis, intestinal secretion and the colonic flora, have been developed for laxative refractory constipation. This review focuses on the evidence for each of these agents, and the relative indications for each of them.