Helicobacter pylori (H. pylori) is a bacteria responsible for most ulcers and many cases of chronic gastritis (inflammation of the stomach). This organism can weaken the protective coating of the stomach and duodenum (first part of the small intestines), allowing the damaging digestive juices to irritate the sensitive lining of these body parts.

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

Interestingly, many people have this organism in their gastrointestinal tract but don't get an ulcer or gastritis. It seems that other factors must also be present for the damage to take place. The factors that increase your risk for an ulcer from H. pylori include:

• Abnormal immune response in your intestines
• Certain lifestyle habits, like coffee drinking, smoking, and ongoing stress

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

• Abdominal pain
• Dyspepsia or indigestion
• Bloating and fullness
• Mild nausea (may be relieved by vomiting)
• Belching and regurgitation
• Feeling very hungry 1 to 3 hours after eating

Simple blood, breath, and stool tests can determine if you are infected with H. pylori. If you have symptoms, your doctor will determine if you are an appropriate candidate for these screening tests.

The most accurate way to diagnose H. pylori, however, is through upper endoscopy of the esophagus, stomach, and first part of the small intestines (duodenum). Because this procedure is invasive, it is generally reserved for people at high risk for ulcers or other complications from H. pylori, like having stomach cancer. Such risk factors include being over 45 or having alarming symptoms like:

• Unexplained weight loss
• Gastrointestinal bleeding
• Anemia
• Difficulty swallowing.

Once diagnosed and treated, the breath and stool tests are used to determine if you have been cured of the infection.