Some common over-the-counter medicines available for diarrhea include Pepto-Bismol, Imodium A-D and Kaopectate, states WebMD. The active ingredients in these medicines are loperamide and bismuth subsalicylate, according to FamilyDoctor.org.
Loperamide slows the speed of food moving through the intestines, which allows the body to absorb more fluid and create solid stools, states FamilyDoctor.org. Bismuth subsalicylate works by balancing the fluid that travels through the intestines while decreasing inflammation and reducing the amount of bacteria that causes diarrhea. Another way to treat diarrhea is to drink plenty of fluids, including sodas without caffeine, chicken broth and sports drinks, according to WebMD.