What is a peptic ulcer and what causes it?

Many years ago, ulcers of the lower end of the stomach and the duodenum (the first part of the small intestine) were thought to be caused by excessive secretion of stomach acid. Because of the enzyme pepsin found in stomach juice, these ulcers were named "peptic ulcers." In the 1960's, the medical literature stated that stress caused ulcers. In the 1970's, doctors believed that high stomach acid levels were the main cause of ulcers; ulcers were treated with antacids and acid lowering drugs. It was always puzzling why the ulcers kept coming back year after year. After 1985, medical research demonstrated that acid plays only a secondary role in ulcer formation. Most ulcers in the bottom part of the stomach and in the duodenum are caused by an infection with a bacterium called Helicobacter pylori or by the use of NSAID's (nonsteroidal anti-inflammatory drugs) such as Ibuprofen, Advil, Motrin, Aleve Naprosyn, or Clinoril. After the bacterium or the drug damages the lining tissue layer, stomach acid seeps into the wall of the stomach or duodenum, causing further damage or inflammation. The reason that ulcers kept returning before this discovery stemmed from the fact that, although the acid was eliminated temporarily, the bacterium was never treated and remained in the stomach to continue causing problems. At present, successful eradication of the Helicobacter pylori infection heals the ulcer and prevents recurrence of the ulcer.