Helicobacter pylori bacteria (H. pylori)
H. pylori is the most common cause of gastric and duodenal ulcers. This bacterium affects the mucus that protects your stomach and small intestine, allowing for stomach acid to damage the lining.
An estimated 30 to 40 percent of U.S. people are infected with H. pylori.
It’s unclear exactly how this bacterium spreads, but researchers believe it’s mostly through unclean food, water, and eating utensils. People who carry H. pylori can also spread it through direct contact with saliva.
Many people get this bacterial infection as a child, but it rarely develops into a peptic ulcer. In fact, most people don’t see symptoms until they’re older — if at all.
People who use or rely on nonsteroidal anti-inflammatory drugs (NSAIDs), such as aspirin, ibuprofen, and naproxen, are more likely to develop peptic ulcers. In fact, after H. pylori, NSAID use is the other major cause of peptic ulcers.
NSAIDs can irritate and damage your stomach and intestinal lining. Acetaminophen (Tylenol) isn’t an NSAID, so it’s often recommended for people who can’t take NSAIDs due to ulcers or other digestive conditions.
A rare condition known as Zollinger-Ellison syndrome causes the development of both cancerous and noncancerous tumors. These tumors release hormones that cause extremely high levels of stomach acid that can lead to gastric and duodenal ulcers.
These tumors most often develop in the pancreas and duodenum, but can occur in other places throughout the body.