PEPTIC ULCER (STOMACH ULCER)A peptic ulcer is an open sore. They are usually found in the lining of the stomach, esophagus, or upper small intestine. Ulcers that occur in the stomach are called gastric ulcers. Ulcers that occur in the upper area of the small intestine, which is called the duodenum, are called duodenal ulcers.What Causes Ulcers?No single cause...