Eating is one of life's greatest joys, but when you're saddled with a stomach ulcer, even this simple pastime can get ruined. Stomach ulcers aren't uncommon. Around 25 million Americans will get one at some point in their lives. Stomach ulcers are also called “peptic ulcers.” What is a stomach ulcer? A stomach or peptic ulcer is a sore in the stomach lining or duodenum (the first part of your small intestine). Chief causes of stomach ulcers are: Helicobacter pylori infection