Loperamide is a medicine used along with other measures to treat diarrhea. Loperamide helps stop diarrhea by slowing down the movements of the intestines. Imodium A-D is used in the treatment of sudden diarrhea such as the traveler's diarrhea. Imodium A-D reduces the number of bowel movements, thereby making the stool less watery. Note that Imodium A-D is only used to treat the symptoms of sudden diarrhea and not the cause.