H. pylori is a type of bacteria—a germ that may cause infection. H. pylori infection is common, particularly in developing countries, and often begins in childhood. Symptoms usually don’t occur until adulthood, although most people never have any symptoms.
H. pylori bacteria can cause peptic ulcers—sores on the lining of the stomach or duodenum.
A peptic ulcer is a sore on the lining of the stomach or duodenum, the beginning of the small intestine. Less commonly, a peptic ulcer may develop just above the stomach in the esophagus, the tube that connects the mouth to the stomach.
A peptic ulcer in the stomach is called a gastric ulcer. One that occurs in the duodenum is called a duodenal ulcer. People can have both gastric and duodenal ulcers at the same time. They also can develop peptic ulcers more than once in their lifetime.
For more information, visit: https://www.niddk.nih.gov/health-information/digestive-diseases/peptic-ulcers-stomach-ulcers