Helicobacter pylori (H. pylori)

What is H. pylori?
H. pylori, or Helicobacter pylori, is a bacterium found in the stomachs of about two-thirds of the world’s population. While most infected people will never develop disease, H. pylori causes most stomach and small intestine ulcers. It has been estimated that between 2 percent to 20 percent of people infected with H. pylori will develop ulcers. This infection also increases the risk of MALT lymphoma, gastric cancer, and possibly pancreatic cancer.

Who is likely to have H. pylori?
H. pylori infection rates are higher in developing nations than in Europe and North America because scientists believe the bacterium is spread through contaminated food and water or direct mouth-to-mouth contact. Poor children living in crowded conditions are most likely to become infected.

What characterizes H. pylori infection?
H. pylori infection can cause abdominal pain but may be painless. The infection is usually not discovered until a physician investigates the cause of stomach pain. In many cases, stomach lining inflammation or ulcers have already developed. Other symptoms of ulcers include loss of appetite or weight, vomiting, bloody stool, or anemia.

How does the pathologist diagnose H. pylori?
If you have symptoms of H. pylori infection, your primary care physician can recommend simple tests for the pathologist to examine. They include a blood antibody test, urea breath test, stool antigen test, and endoscopic biopsy. While the blood, breath, and stool tests can verify the presence of an infection, a biopsy is required to examine the inflammation and ulcers H. pylori causes. During the biopsy procedure, a physician inserts a flexible viewing tube (endoscope) through the mouth, down the esophagus, and into the stomach and small intestine. The physician operates tiny forceps at the end of the tube to remove small tissue samples, or biopsies, from the ulcerated or inflamed areas for the pathologist to examine under a microscope.

How do doctors determine what treatment will be necessary?
While antacids and medications that decrease the secretion of stomach acid can treat ulcers effectively, these treatments cannot remove H. pylori from the stomach. As a result, ulcers often return after the medications are discontinued. If ulcers are present, H. pylori should be eradicated not only to stop the discomfort of ulcers but also to reduce the risk of MALT lymphoma and other cancers.

Because H. pylori is resistant to commonly used antibiotics, physicians often prescribe two or more antibiotics along with other medications containing compounds to destroy the bacterium.  These combinations cure 70 to 90 percent of the infections. Because prior exposure to certain antibiotics may cause the first combination to be unsuccessful, a physician sometimes must find another combination to treat the infection successfully. Physicians use the urea breath test or the stool antigen test to confirm the eradication of H. pylori. In addition to receiving treatment to eradicate H. pylori, patients are treated for the condition created by H. pylori – ulcers in most cases and MALT lymphoma in some situations. MALT lymphoma tumors usually regress quickly after H. pylori is destroyed.

Individuals infected with H. pylori who did not have ulcers or MALT lymphoma are usually not treated because of the side effects of the antibiotic treatment and the rarity of gastric cancer even among those with H pylori. Future research may help physicians to select more accurately individuals who are prone to ulcers and cancers and need treatment when symptoms are not present.

While most individuals with H. pylori do not develop cancer, they do have an increased risk of this disease. For this reason, individuals with H. pylori should receive regular physician care and take actions to manage the risk factors associated with gastric cancer. These risk factors include chronic gastritis (stomach inflammation); a diet high in salted, smoked, or poorly preserved foods and low in fruits and vegetables; certain types of anemia; smoking; diabetes; and obesity.

Each year in the United States, there are more than 22,000 new cases of gastric cancer and about 11,500 deaths due to this disease. Each year, more than 32,000 new cases of pancreatic cancer are diagnosed in the United States and about 31,000 people die from this disease, making it the nation’s fifth leading cause of cancer deaths.

For more information,go to www.cancer.gov (National Cancer Institute) or www.medicinenet.com (Medicine Net, a service of Web MD). Type the keywords H. pylori into the search box.

What kinds of questions should I ask my doctors?
Ask any question you want. There are no questions you should be reluctant to ask. Here are a few to consider:

  • Please describe the type of cancer I have and what treatment options are available.
  • What treatment options do you recommend? Why do you believe these are the best treatments?
  • What are the pros and cons of these treatment options?
  • What are the side effects?
  • Is your medical team experienced in treating the type of cancer I have?
  • Can you provide me with information about the physicians and others on the medical team?
  • If I want a second opinion, could you provide me with the names of physicians and/or institutions that you would recommend?


Antibiotic: A drug used to treat a bacterial infection.

Gastric: Relating to the stomach.

MALT lymphoma: Mucosa-associated lymphoid tissue (MALT) lymphoma is a type of gastric cancer associated with H. pylori bacterium infection. The risk of developing MALT lymphoma is six times higher in those infected with H. pylori than in uninfected people.

Ulcers: Painful holes or abrasions in the lining of the stomach or upper small intestine, caused in many cases by H. pylori.

Pathologist: A physician who examines tissues and fluids to diagnose disease in order to assist in making treatment decisions.



Stomach with H. pylori infection  NORMAL

Stomach with H. pylori infection.
Stomach without H. pylori infection.
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This information was developed by the College of American Pathologists’ Public Affairs Committee in conjunction with the College’s Cancer Committee and Council on Scientific Affairs. The College is providing this information to help you better understand your health. Ultimately any decisions you make about your health, however, should be between you and your doctor.

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