What is the primary function of bulking agents in laxatives?

Bulking agents in laxatives primarily function by retaining water in the stool and increasing its mass. When these agents are ingested, they absorb liquids and swell, creating a bulkier stool that is easier to pass. This increase in stool volume stimulates intestinal peristalsis, the wave-like muscle contractions that move stool through the digestive tract.

By causing a gradual increase in satiety and stimulating the bowel, bulking agents help to alleviate constipation by promoting a more regular bowel movement pattern. Unlike other laxative categories, such as stimulant laxatives that directly stimulate nerve endings or osmotic laxatives that draw water into the bowel, bulking agents act primarily by enhancing the physical characteristics of the stool itself. This makes them particularly useful for managing chronic constipation and is generally considered a first-line treatment option.