Laxative medications are typically given in liquid, pill, or suppository form and may be prescribed to treat constipation that is not responding to other treatments. The use of laxatives (except bulk-forming laxatives) on a regular basis is typically not recommended, except in certain circumstances and on the advice of a physician. A physician will be able to make the determination as to which laxative will be most effective in each particular case.
Several types of laxatives are available over-the-counter in drug stores.
- Bulk-forming laxatives (such as FiberCon, Metamucil, and Citrucel) are made of a type of fiber that is not absorbed by the intestine, but instead passes through it. This has the effect of absorbing water and softening stool, which makes having a bowel movement easier. Bulk-forming laxatives can be safely used long-term.
- Emollient laxatives called "stool softeners" allow more fat and water into the stool, which makes the stool softer and easier to pass.
- Lubricant laxatives, such as mineral oil, work by coating the stool in an oil, which makes it difficult for water to be withdrawn. The extra water helps to keep the stool soft.
- Hyperosmotic laxatives, such as milk of magnesia or Epsom salt, aid digestion by causing more water to be drawn into the intestine to keep stool soft.
- Stimulant laxatives, such as castor oil, cause the movement of the intestines (peristalsis) to speed up, and stool is passed through at a faster than normal rate.
- Natural laxatives are foods that tend to have mild laxative properties, such as prunes. Other foods that may help relieve constipation include prune juice, figs, licorice, rhubarb, and foods that are high in fiber.
Laxatives may also be given to clean the bowel in preparation for a test, such as colonoscopy, or before surgery. These types of laxatives are typically used under the care of a physician.