Helicobacter pylori is a gram-negative bacterium that is found in the human stomach. It is responsible for various gastrointestinal diseases, including peptic ulcers and gastritis. There are several synonyms for the word "Helicobacter," such as Campylobacter pylori, Pylori bacterium, H. pylori, and gastric bacterium. Some researchers also refer to it as the ulcer bacterium due to its association with peptic ulcers. Despite being known for its adverse effects on human health, Helicobacter pylori is also widely used in research laboratories for various purposes, including in the study of gastrointestinal diseases and the development of medical treatments.