Overview. Bismuth subsalicylate, an active ingredient in the popular medication Pepto-Bismol, is used for the treatment of nausea, heartburn, indigestion, upset stomach, diarrhea, and other temporary discomforts of the stomach and gastrointestinal tract (including duodenal and peptic ulcers, ulcerative colitis, and diarrhea [1–5].It is …Web