Helicobacter pylori (H. pylori) is a type of bacteria that infects the stomach lining. It is a common cause of peptic ulcers and can lead to chronic gastritis and, in some cases, stomach cancer. This bacterium is usually acquired in childhood and can persist for life if not treated. Symptoms of an H. pylori infection can include abdominal pain, bloating, nausea, and loss of appetite, but many people may not experience any symptoms. Diagnosis is typically made through breath, blood, stool, or tis