Read condition-specific symptoms and clinical context for Helicobacter pylori. A stomach colonizer associated with inflammation and ulcer disease.
H. pylori is a curved or spiral bacterium that colonizes the mucus lining the human stomach. Infection may cause no noticeable symptoms. Persistent infection can cause stomach inflammation and peptic ulcers, and increases the risk of certain gastric cancers. Ulcer symptoms overlap with other conditions and do not establish H. pylori infection.
Possible ulcer symptoms. H. pylori is one cause; some ulcers have other causes.
Possible symptoms: Upper abdominal pain; Early or uncomfortable fullness; Nausea or vomiting; Bloating or belching.
Seek medical care immediately for black or bloody stool, blood in vomit, fainting, or severe persistent abdominal pain.
Many people with infection do not notice symptoms; even an ulcer can sometimes be silent.
Carriage or infection can be present without the disease symptoms listed above.
Clinical context and appropriate testing distinguish carriage from illness.
Source check: 2026-09-19. Educational content; independent scientific review remains pending.