A substance used to prevent or treat diarrhea. Antidiarrheal medications come in various forms. Intestinal flora modifiers: L. acidophilus (Lactinex): Opiates: paregoric, opium tincture, codeine, loperamide (Imodium), diphenoxylate (Lomotil): Adsorbents: bismuth subsalicylate (Pepto-Bismol), kaolin-pectin, activated charcoal, attapulgite (Kaopectate) and Anticholinergics: belladonna alkaloids (Donnatal), atropine