A crater-like sore in tissue, most commonly referring to such a sore in the stomach or upper part of the small intestine (the duodenum). An estimated 1 in 10 Americans will develop one of these ulcers, called a peptic ulcer, at some point in their lives. When a peptic ulcer is shallow, it’s called an erosion.
The stomach and duodenum are constantly bathed in highly corrosive digestive juices and stomach acid. Normally, this isn’t a problem because the lining of the stomach and duodenum protects them. Sometimes, however, this protective system breaks down, and the acid and digestive juices are able to eat through the lining causing an ulcer. Infection with the bacterium Helicobacter pylori plays an important role in the development of ulcers by weakening the protective lining. H. pylori is estimated to be present in about half the people in the world, but it causes ulcers only in some people.
A peptic ulcer is also a serious side effect of nonsteroidal anti-inflammatory drugs (NSAIDs) used to treat arthritis. Traditional NSAIDs, which include ibuprofen (brand name Advil) and naproxen sodium (Aleve), block the production of substances called prostaglandins that ordinarily protect the lining of the stomach and duodenum from injury. Celecoxib (Celebrex), a newer type of NSAID called a COX-2 inhibitor, may lower the risk of peptic ulcers, as can taking a proton pump inhibitor (PPI). PPIs, which include esomeprazole (Nexium) and omeprazole (Prilosec), help to protect the lining of the stomach and duodenum by reducing stomach acid.