Table 1.

Types of laxatives

TREATMENT	MECHANISM OF ACTION	EXAMPLES
Bulk-forming agents	Luminal water binding increases stool’s bulk, making it easier to pass5	Psyllium, bran
Stool softeners	Stimulates net secretion of water, sodium, chloride, and potassium and inhibits net absorption of glucose and bicarbonate in the jejunum6	Docusate sodium or calcium
Lubricant laxatives	Decreases surface tension of bowel’s liquid contents so that more liquid remains in the stool, thereby facilitating evacuation and decreasing straining2	Mineral oil
Osmotic laxatives	Increases osmolar tension, resulting in increased water collection, distention, peristalsis, and evacuation2	Salts (eg, sodium chloride, potassium chloride), magnesium sulfate or citrate, lactulose, sorbitol, polyethylene glycol
Stimulant laxatives	Acts locally to stimulate colonic motility and decrease water absorption from large intestine5	Bisacodyl, senna

Data from West et al,² Tack et al,⁵ and Moriarty et al.⁶