Pepto-Bismol contains bismuth subsalicylate, which is commonly used in combination with other medications to treat peptic ulcers. These sores on the stomach lining are caused by a type of bacteria called H. pylori. Ulcers can be quite painful but respond well to proper treatment. Doctors usually treat peptic ulcers with a drug regimen that includes bismuth subsalicylate and antibiotics, which are medications that kill bacteria. The standard regimen, sometimes called triple therapy, also includes medicine that reduces stomach acid levels. Bismuth protects sores from stomach acid and helps to eliminate the ulcer-causing bacteria. However, taking Pepto-Bismol alone will not cure an ulcer. If you have persistent stomach pain, see your doctor.