What is an H. pylori infection?

H. pylori is a common type of bacteria that grows in the digestive tract and has a tendency to attack the stomach lining. It infects the stomachs of roughly 60 percent of the world’s adult population. H. pylori infections are usually harmless, but they’re responsible for the majority of ulcers in the stomach and small intestine.

The “H” in the name is short for Helicobacter. “Helico” means spiral, which indicates that the bacteria are spiral shaped.

H. pylori often infect your stomach during childhood. While infections with this strain of bacteria typically don’t cause symptoms, they can lead to diseases in some people, including peptic ulcers, and an inflammatory condition inside your stomach known as gastritis.

H. pylori are adapted to live in the harsh, acidic environment of the stomach. These bacteria can change the environment around them and reduce its acidity so they can survive. The spiral shape of H. pylori allows them to penetrate your stomach lining, where they’re protected by mucus and your body’s immune cells are not able to reach them. The bacteria can interfere with your immune response and ensure that they’re not destroyed. This can lead to stomach problems.

It’s still not known exactly how H. pylori infections spread. The bacteria have coexisted with humans for many thousands of years. The infections are thought to spread from one person’s mouth to another. They may also be transferred from feces to the mouth. This can happen when a person does not wash their hands thoroughly after using the bathroom. H. pylori can also spread through contact with contaminated water or food.

The bacteria are believed to cause stomach problems when they penetrate the stomach’s mucous lining and generate substances that neutralize stomach acids. This makes the stomach cells more vulnerable to the harsh acids. Stomach acid and H. pylori together irritate the stomach lining and may cause ulcers in your stomach or duodenum, which is the first part of your small intestine.

Most people with H. pylori don’t have any symptoms.

When the infection leads to an ulcer, symptoms may include abdominal pain, especially when your stomach is empty at night or a few hours after meals. The pain is usually described as a gnawing pain, and it may come and go. Eating or taking antacid drugs may relieve this pain.

If you have this type of pain or a strong pain that doesn’t seem to go away, you should visit your doctor.

A number of other symptoms may be associated with H. pylori infection, including:

See your doctor immediately if you experience:

  • trouble swallowing
  • anemia
  • blood in the stool

However, these are common symptoms that could be caused by other conditions. Some of the symptoms of H. pylori infection are also experienced by healthy people. If any of these symptoms persist or you’re concerned about them, it’s always best to see your doctor. If you notice blood or a black color in your feces or vomit, you should consult your doctor.

Children are more likely to develop an H. pylori infection. Their risk is higher mostly due to lack of proper hygiene.

Your risk for infection partly depends on your environment and living conditions. Your risk is higher if you:

  • live in a developing country
  • share housing with others who are infected with H. pylori
  • live in overcrowded housing
  • have no access to hot water, which can help to keep areas clean and free from bacteria
  • are of non-Hispanic Black or Mexican American decent

It’s now understood that peptic ulcers are caused by this type of bacteria, rather than stress or eating foods high in acid. About 10 percent of people infected with H. pylori develop a peptic ulcer, according to the Mayo Clinic. Long-term use of nonsteroidal anti-inflammatories (NSAIDs) also increases your risk of getting a peptic ulcer.

Your doctor will ask about your medical history and family history of disease. Be sure to tell your doctor about any medications you’re taking, including any vitamins or supplements. If you’re experiencing symptoms of a peptic ulcer, your doctor will likely ask you specifically about your use of NSAIDs, such as ibuprofen.

Your doctor may also perform many other tests and procedures to help confirm their diagnosis:

Physical exam

During a physical exam, your doctor will examine your stomach to check for signs of bloating, tenderness, or pain. They’ll also listen for any sounds within the abdomen.

Blood test

You may need to give blood samples, which will be used to look for antibodies against H. pylori. For a blood test, a healthcare provider will draw a small amount of blood from your arm or hand. The blood will then be sent to a laboratory for analysis. This is only helpful if you have never been treated for H. pylori before.

Stool test

A stool sample may be needed to check for signs of H. pylori in your feces. Your doctor will give you a container to take home with you to catch and store a sample of your stool. Once you return the container to your healthcare provider, they will send the sample to a laboratory for analysis. This and the breath tests usually will require you to stop medications such as antibiotics and proton pump inhibitors (PPIs) before the test.

Breath test

If you have a breath test, you’ll swallow a preparation containing urea. If H. pylori bacteria are present, they will release an enzyme that breaks down this combination and will release carbon dioxide, which a special device then detects.


If you have an endoscopy, your doctor will insert a long, thin instrument called an endoscope into your mouth and down into your stomach and duodenum. An attached camera will send back images on a monitor for your doctor to view. Any abnormal areas will be inspected. If necessary, special tools used with the endoscope will allow your doctor to take samples from these areas.

H. pylori infections can lead to peptic ulcers, but the infection or the ulcer itself can lead to more serious complications. These include:

  • internal bleeding, which can happen when a peptic ulcer breaks through your blood vessel and is associated with iron deficiency anemia
  • obstruction, which can happen when something like a tumor blocks the food from leaving your stomach
  • perforation, which can happen when an ulcer breaks through your stomach wall
  • peritonitis, which is an infection of the peritoneum, or the lining of the abdominal cavity

Studies show that infected people also have an increased risk of stomach cancer. While the infection is a major cause of stomach cancer, most people infected with H. pylori never develop stomach cancer.

If you have an H. pylori infection that isn’t causing you any problems and you aren’t at increased risk of stomach cancer, treatment may not offer any benefits.

Stomach cancer, along with duodenal and stomach ulcers, is associated with H. pylori infection. If you have close relatives with stomach cancer or a problem such as a stomach or duodenal ulcer, your doctor may want you to have treatment. Treatment can cure an ulcer, and it may reduce your risk of developing stomach cancer.


You will normally need to take a combination of two different antibiotics, together with another drug that reduces your stomach acid. Lowering stomach acid helps the antibiotics work more effectively. This treatment is sometimes referred to astriple therapy.

Some of the drugs that are used in a triple therapy treatment include:

  • clarithromycin
  • proton-pump inhibitors (PPI), such as lansoprazole (Prevacid), esomeprazole (Nexium), pantoprazole (Protonix), or rabeprazole (AcipHex)
  • metronidazole (for 7 to 14 days)
  • amoxicillin (for 7 to 14 days)

Treatment may vary depending on your past medical history and if you have allergies to any of these medications.

After treatment, you will have a follow-up test for H. pylori. In most cases, only one round of antibiotics is needed to clear the infection, but you might need to take more, using different drugs.

Lifestyle and diet

There’s no evidence that food and nutrition play a role in preventing or causing peptic ulcer disease in people infected with H. pylori. However, spicy foods, alcohol, and smoking may worsen a peptic ulcer and prevent it from healing properly. Read about natural treatments for the H. pylori infection.

For many people infected with H. pylori, their infections never cause any difficulties. If you’re experiencing symptoms and receive treatment, your long-term outlook is generally positive. At least four weeks after finishing your treatment, your doctor will check to make sure it worked. Depending on your age and other medical issues, your doctor may use a urea or stool test to check whether your treatment worked.

If you develop diseases associated with an H. pylori infection, your outlook will depend on the disease, how soon it’s diagnosed, and how it’s treated. You may need to take more than one round of treatment to kill the H. pylori bacteria.

If the infection is still present after one round of treatment, a peptic ulcer could return or, more rarely, stomach cancer could develop. Very few people infected with H. pylori will develop stomach cancer. However, if you have a family history of stomach cancer, you should get testing and treatment for H. pylori infection.