Peptic ulcers occur when stomach acid and other digestive juices erode the inner lining of the stomach or the first part of the small intestine. This inner lining is a complex mucous barrier that protects the gastrointestinal (GI) lining from the corrosive acids and other chemicals that the stomach produces to digest food. When the barrier breaks down, the lining is exposed to the destructive potential of the digestive juices.

For many years, scientists believed that acidic foods and stress caused peptic ulcers and treated the ulcers with surgery and medications to lessen the symptoms. However, research conducted in the 1980s revealed that the most common cause of peptic ulcers is infection by bacteria called Helicobacter pylori, which can survive in the acidic environment of the stomach. The bacteria can produce a change in the mucous barrier, which causes ulcers.

In addition to bacteria, some medications that irritate the GI lining can also cause peptic ulcers. For example, chronic use of pain relievers such as nonsteroidal anti-inflammatory drugs (NSAIDs) may alter the balance of the mucous barrier in the stomach and make it more susceptible to ulcers.

For both of these major causes of peptic ulcers (bacteria and medications), the mechanisms are not well understood. Each has been identified as a cause, but many people carry the bacteria or take NSAIDs and do not develop ulcers.

The most common symptom of peptic ulcer is mild to moderately severe pain just below the breastbone.  The pain often occurs once or a few times daily, typically two to three hours after eating. It generally lasts from one to several weeks, then disappears for a while. Other symptoms may include heartburn and nausea and vomiting. Some people may experience no symptoms and become aware of their ulcers when complications develop. Potential complications of peptic ulcers include bleeding, penetration to other organs, perforation and obstruction.

Peptic ulcers are usually diagnosed following an evaluation of medical history, a physical examination and diagnostic tests. Some physicians may simply treat for peptic ulcers if a patient’s medical history and physical examination strongly suggest their presence. However, tests are usually needed to confirm the diagnosis and determine the cause of the ulcers. A common testing procedure is endoscopy, in which a flexible tube with a camera is inserted through the mouth and down to the stomach to view the lining.