Psyllium is a fiber laxative known as a "bulk former" because psyllium treats constipation by absorbing liquid already in the intestine to create one large stool that is easy to pass. The presence of large mass in the intestine stimulates the bowel movement, relieving constipation.
Other laxatives include hyperosmotics, lubricants, stimulants, and emollients. Some laxatives include a combination of these types. Hyperosmotics may be saline or sugar-based, and draw water into the bowel from surrounding body tissues, softening the stool and stimulating a bowel movement. Lubricants, such as mineral oil, coat the stool, keeping moisture inside and making the stool easy to pass. Stimulant laxatives increase muscle contraction of the intestinal wall, helping to move along a stool. Emollients draw moisture into the stool. Emollient laxatives do not stimulate a bowel movement, but ensure that the stool is soft and a bowel movement can occur without strain. If you suffer from constipation or other bowel problems, you should choose an appropriate laxative based on the type and severity of your condition.
Discuss the potential benefits and risks of different laxatives with your doctor to determine the best option for your treatment.