Metamucil is a laxative that is utilized to treat constipation and irregular bowel movements, according to Drugs.com. Metamucil contains psyllium, a substance that helps to pull moisture into the intestines and soften hardened stool.
Metamucil also adds bulk to stool, which can help to encourage intestinal movement and make it easier to move the bowels, according to WebMD. Psylium has been used in conjunction with healthy diets to help lower high cholesterol levels.
Side effects of using Metamucil can include intestinal gas and stomach cramps, WebMD adds. Metamucil must be taken with a full glass of water to prevent the psyllium from swelling in the throat, as this can lead to swallowing difficulty or choking.