Glycerin also has lubricating and softening properties that ease evacuation. Lubricant: An agent that lubricates the contents of the intestinal tract, which coats the stool mass to keep moisture in, thereby helping to soften the stool mass and make it easier to pass. Glycerin rectal is a laxative medication administered rectally in the form of suppositories, to relieve occasional constipation in both adults and children.For example, Fleet® Liquid Glycerin and Glycerin Suppositories. Hyperosmotic: An agent that attracts water into the stool and promotes a bowel movement.Carbon dioxide-releasing: A suppository agent that contains ingredients that release carbon dioxide, which then induces gentle pressure in the rectum and promotes a bowel movement.Bulk-forming: An agent that increases bulk volume and water content of the stool, which then promotes a bowel movement.Laxatives are grouped into the following categories:
