H-Pylori is a bacteria that infects the stomach and esophagus. This can cause symptoms such as trouble swallowing-heartburn-acid reflux-GERD-excessive belching and ulcers. It is actually a naturally occurring bacteria that is indigenous to the upper GI. It is supposed to be there only now it has overgrown & is dominating the territory.
It is supposed to be kept in check by the surrounding beneficial bacteria.