Imodium slows the rhythm of digestion so that the small intestines have more time to absorb fluid and nutrients from the foods you eat. Imodium is used to treat diarrhea. Imodium controls symptoms of diarrhea, including Traveler's Diarrhea. It works by slowing the activity of the intestines and affecting the movement of water and chemicals through the bowel. It can be purchased over the counter in liquid and capsule form under the brand name Imodium A-D.