Helicobacter pylori is a type of bacteria that lives in the stomach. It can cause infections that lead to various digestive issues, such as ulcers and gastritis. Many people carry this bacteria without any symptoms, but for some, it can lead to discomfort and serious health problems. The bacteria are usually spread through contaminated food or water. Doctors can diagnose an H. pylori infection through breath, blood, or stool tests. Treatment typically involves antibiotics and medications to reduce stomach acid, helping to eliminate the bacteria and heal the stomach lining.