A duodenal ulcer occurs when an area of the lining of the intestine is eaten away by stomach acid and digestive juices. The lining of the intestine is normally protected from stomach acids. However, under certain conditions the protection fails and ulcers can result. The most common cause of duodenal ulcers is a type of bacteria called Helicobacter pylori, also called H. pylori. Other common causes of ulcers include anti-inflammatory medications such as aspirin, ibuprofen, and naproxen.
Stress also appears to contribute to ulcers.
This includes both emotional stress and the sudden physical stress of a severe illness or injury. Chemicals that seem to work with these common causes to produce ulcers include nicotine, caffeine, and alcohol. People with a family history of duodenal ulcers are more likely to get ulcers. The problem is four times more common in men than in women. Most cases of ulcers occur between ages 40 and 50.