Helicobacter pylori -bacteria of genus Helicobacter-is present in human gastric mucosa and plays an ethiological role in acid-peptic conditions, both benign and malignant, such as gastritis, gastric and duodenal peptic ulcers, gastric adenocarcinoma and non- Hodgkin lymphoma of lymphoid tissue presentin gastric mucosa (MALT).Since early diagnosis and treatment are relevant, interest have been placed on studying risk factors, contagiousness and prevalence, facts related to public health. New research has shown H. heilmanni, felis and rappini in pet’s gastric mucosa, with an eventual zoonotic component for a possible infection of human gastric mucosa.