Which laxative type increases the osmotic load of the gastrointestinal tract?

• A. Bulk-Forming laxative
• B. Stimulant laxative
• C. Emollient laxative
• D. Saline laxative

Answer: (D)

Osmotic activity in the GI tract is what saline laxatives use to produce a bowel movement. They contain salts such as magnesium or phosphate that aren’t well absorbed. These osmotically active particles stay in the intestinal lumen and pull water from the body into the lumen, increasing stool water content and softening stools, which speeds transit. This rise in osmotic load is the key effect. By contrast, bulk-forming laxatives work mainly by absorbing water to swell the stool, stimulant laxatives boost motility through nerve stimulation, and emollient laxatives soften stool by reducing surface tension rather than drawing water osmotically.