So H. pylori is a bacteria that resides in some people's stomachs. We don't know how we get infected. We don't know if it's people to people, or if it's food to food. We're not quite sure how it get's to us, but, basically these bacteria live in the stomach and, it can cause ulcers, and gastritis, and in worst case scenarios can also cause stomach cancers. So if you have an ulcer, or if you're having some stomach pain and your doctor tests you for the H. pylori, they're going to put you on antibiotics, and an acid blocking medication to heal the ulcer that's caused by the H. pylori infection. The H. pylori is the nickname for Helicobacter pylori.