Helicobacter pylori (H. pylori) is a type of bacteria that infects your stomach. It can cause sores and inflammation in the lining of your stomach or the upper part of your small intestine (the. H. pylori infections occur across the world due to exposure to saliva or stool in contaminated water or food. Learn how the bacterium is spread and treated with antibiotics. H. pylori (Helicobacter pylori) is a type of bacteria that infects your stomach and small intestine. These bacteria damage the lining of your stomach over time, which can lead to irritation, gastritis or peptic ulcers. H. pylori often causes no symptoms, but when it does, here’s how to recognize them and which tests actually confirm an active infection. H pylori symptoms can include bloating, loss of appetite, stomach burning, nausea, burping, excess gas, vomiting, and dark or bloody stools. Diagnosis and treatment help prevent gastritis, ulcers, and long-term complications. H. pylori (Heliobacter pylori) is a type of bacteria that infects your stomach. It can damage the tissue in your stomach and the first part of your small intestine (the duodenum). In some cases it can also cause painful sores called peptic ulcers in your upper digestive tract. It's caused by a germ called Helicobacter pylori, a bacteria also known as H. pylori. More than half the people in the world may have an H. pylori infection at some point in their lives. These infections often happen during childhood, especially in developing countries. Overview What is an H. pylori infection? H. pylori (Helicobacter pylori) is a type of bacteria that infects your stomach. It’s the most common chronic bacterial infection in humans. It affects more than half of the world’s population. But it doesn’t cause illness in most people. If you're concerned about an H. pylori infection, talk with your healthcare professional. Together you can decide whether H. pylori testing might be right for you. We counsel patients that H. pylori eradication is associated with peptic ulcer healing, reduces the likelihood of ulcer recurrence, reduces the risk of gastric cancer, and, in symptomatic individuals, may improve or resolve dyspepsia symptoms.