Helicobacter pylori

Alternative Names

Gastritis – ;

Definition of Helicobacter pylori

() is the bacteria responsible for most ulcers and many cases of stomach inflammation (chronic gastritis).

Causes, incidence, and risk factors

As many as half of the world’s population is infected with . Those living in developing countries or crowded, unsanitary conditions are most likely to contract the bacterium, which is passed from person to person. only grows in the stomach, and is usually contracted during childhood.


If you are a carrier of , you may have no symptoms. If you have an ulcer or gastritis, you may have some of the following symptoms:

Signs and tests

Simple blood, breath, and stool tests can determine if you are infected with . If you have symptoms, your doctor will determine if you should have these screening tests.


Patients who have and also have an ulcer are most likely to benefit from being treated. Patients who only have heartburn or acid reflux and are less likely to benefit from treatment. The treatment does not work in all patients.

Expectations (prognosis)

Once the bacteria are gone from your body, the chance of being infected again is very low.


Reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc., and George F Longstreth, MD, Department of Gastroenterology, Kaiser Permanente Medical Care Program San Diego, California. – 8/1/2009

Digestive system

ADAM Medical Encyclopedia

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