Introduction

A peptic ulcer is an open sore or raw area that tends to develop in one of two places:

• The lining of the stomach (called gastric ulcers), or
• The upper part of the small intestine--the duodenum (called duodenal ulcers). In the US, duodenal ulcers are three times more common than gastric ulcers.

A peptic ulcer is an open sore or raw area in the lining of the stomach (gastric) or the upper part of the small intestine (duodenal).

Ulcers average between one-quarter and one-half inch in diameter. They develop when digestive juices produced in the stomach, intestines, and digestive glands damage the lining of the stomach or duodenum.

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The two important digestive juices are hydrochloric acid and the enzyme pepsin. Both substances are critical in the breakdown and digestion of starch, fat, and proteins in food. They play different roles in ulcers:

Click the icon to see an image of the stomach

• Hydrochloric acid. A common misbelief is that excess hydrochloric acid, which is secreted in the stomach, is solely responsible for producing ulcers. Acid output in patients with duodenal ulcers does tend to be higher than normal, but in most patients with gastric ulcers, acid production is usually normal or lower than normal. Some stomach acid, in fact, is important for protecting against H. pylori--the bacteria that has been the cause of most peptic ulcers. [Note: One exception is ulcers that occur in Zollinger-Ellison syndrome. This is a rare genetic condition in which very high levels of gastrin, a potent acid, is secreted by tumors in the pancreas or duodenum.
• Pepsin. Pepsin is an enzyme that breaks down proteins in food. Since the stomach and duodenum are also composed of protein, however, they too are susceptible to the actions of pepsin. Pepsin is, then, also important in the formation of ulcers.