Laxatives (purgatives, aperients) are foods, compounds, or drugs taken to induce bowel movements or to loosen the stool most often taken to treat costipation . Certain stimulant, lubricant, and saline laxatives are used to evacuate the colon for rectal and/or bowel examinations, and may be supplemented by enemas under certain circumstances. Sufficiently high doses of laxatives cause diarrhoea. Laxatives work to increase the movement of fecal matter along the colon.