This medication is used to treat occasional upset stomach, heartburn, and nausea. It is also used to treat diarrhea and help prevent travelers' diarrhea. It works by helping to slow the growth of bacteria that might be causing the diarrhea. This product should not be used to self-treat diarrhea if you also have a fever or blood/mucus in the stools. These could be signs of a serious health condition. Consult your doctor promptly for proper evaluation and treatment if you have these symptoms. This medication is used under a doctor's direction with other medication to treat stomach ulcers caused by a certain bacteria (Helicobacter pylori). Do not use this medication to self-treat ulcers. Bismuth subsalicylate is a salicylate. Salicylates can cause serious bleeding problems when used alone in patients with ulcers. Check the ingredients on the label even if you have used the product before. The manufacturer may have changed the ingredients. Also, products with similar names may contain different ingredients meant for different purposes. Taking the wrong product could harm you.