Psyllium is mainly used as a dietary fiber, which is not absorbed by the small intestine. The purely mechanical action of psyllium mucilage absorbs excess water while stimulating normal bowel elimination. Although its main use has been as a laxative, it is more appropriately termed a true dietary fiber and as such can help reduce the symptoms of both constipation and mild diarrhea. The laxative properties of psyllium are attributed to the fiber absorbing water and subsequently softening the stool. It is also one of the few laxatives not to promote flatulence.