What causes peptic ulcers?

It is believed that lifestyle, as well as acid and pepsin play a role in ulcer development. However, research shows that 90 percent of duodenal ulcers develop as a result of infection with a bacterium called Helicobacter pylori (H. pylori). The bacterium produces substances that weaken the stomach's protective mucus and make it more susceptible to the damaging effects of acid and pepsin.

Most peptic ulcers are caused by the following:

• Helicobacter pylori (H. pylori), a germ that causes infection
• Nonsteroidal anti-inflammatory drugs (NSAIDs), such as aspirin and ibuprofen

H. pylori is the most common cause of peptic ulcers. Doctors think H. pylori may be spread through unclean food or water or by mouth-to-mouth contact, such as kissing. Even though many people have an H. pylori infection, most of them never develop an ulcer.

Use of NSAIDs is the second-most common cause of peptic ulcers. But not everyone who takes NSAIDs gets a peptic ulcer. Ulcers caused by NSAIDs are more often found in people who:

• Are age 60 or older
• Are female
• Have taken NSAIDs for a long time
• Have had an ulcer before

Other causes of peptic ulcers are rare. One rare cause is Zollinger-Ellison syndrome -- a disease that makes the body produce too much stomach acid, which harms the lining of the stomach or duodenum.

Stress or spicy food does not cause peptic ulcers, but either can make ulcers worse and keep them from healing.

This answer is based on source information from the National Institute of Diabetes and Digestive and Kidney Diseases.

Even though duodenal and gastric ulcers occur at different locations, both appear to be the result of factors damaging the protective lining of the stomach or duodenum. These factors include too much gastric acid, which can be caused by a low-fiber diet, the bacterium Helicobacter pylori (H. pylori), and various drugs, such as nonsteroidal anti-inflammatory drugs and prednisone.

The two most common causes of peptic ulcers are:

• Infection with Helicobacter pylori (H. pylori) bacteria. Although many people are infected with H. pylori bacteria, only a few get ulcers.
• Nonsteroidal anti-inflammatory drugs (NSAIDs). When used for weeks or months, NSAIDs can damage the lining of the digestive tract, causing an ulcer or making an existing ulcer worse. NSAIDs include ibuprofen and naproxen.

A rare cause of peptic ulcers is Zollinger-Ellison syndrome. In this condition, the stomach makes too much acid, damaging the stomach lining.

Although there is no evidence to prove that emotional or mental stress causes ulcers, it does seem to make ulcers worse in some people. But the connection is still controversial.

In the early 1980s, researchers made a major discovery. They identified Helicobacter pylori, a spiral bacterium with an affinity for the stomach, as a major culprit in ulcer disease. H. pylori is the cause of many peptic ulcers. At least 90% of people with duodenal ulcers and 75% to 85% of those with gastric (stomach) ulcers are infected with this organism.

The percentage of ulcers that are not caused by H. pylori has increased; researchers are not yet sure why. Other causes of ulcers include irritating substances such as aspirin, ibuprofen, and other nonsteroidal anti-inflammatory drugs (NSAIDs). Cigarette smoking impairs the healing of ulcers, and stress appears to aggravate ulcer symptoms. Studies show there's also a genetic component, as peptic ulcers sometimes run in families. They occur more often in people with type O blood than in those with other blood types. Sometimes there is no known cause.