Helicobacter pylori

Also called H. pylori

Helicobacter pylori (H. pylori) is a type of bacteria that can infect your gut (stomach).

Key points

  1. Most people with H. pylori infection do not have symptoms.
  2. Some people with H. pylori infection can develop gastritis (stomach inflammation) and stomach ulcers.
  3. Most people pick up the infection as children. It is most likely spread through water and food contaminated with poo.
  4. H. pylori can be treated with 2 antibiotics plus another type of medicine called a proton pump inhibitor (PPI). This is referred to as eradication therapy.
  5. In New Zealand, the rate of H. pylori infection is a lot higher in Māori and Pasifika people.

What is H. pylori infection?

H. pylori is a bacteria that is commonly found in your stomach. It is most likely to be spread through food and water contaminated with faecal matter (poo). There is greater risk of spread in areas with overcrowded living conditions, poor hygiene and unsafe drinking water.

It is thought that the bacteria are usually picked up in childhood and that it is rare to pick them up as an adult.

The infection does not go away naturally, but most people never develop symptoms. It's not known why some people get problems from the bacteria but not others. It can cause digestive problems by damaging the protective lining of your stomach and causing inflammation. This can increase the chance of developing:

  • dyspepsia (indigestion)
  • peptic ulcers (stomach or duodenal ulcers)
  • acute and chronic gastritis (inflammation of your stomach lining)
  • stomach cancer (rare).

Not all people with ulcers have H. pylori. Certain pain reliever medications (eg, aspirin, ibuprofen, naproxen) can also cause ulcers. Ulcers are also more common in smokers. Read more about ulcers

In New Zealand, the rate of H. pylori infection is lower than many other developed countries, with an average rate of 18.6%. However, this rate varies depending on ethnic group:

  • About 7 in every 100 Pakeha people are infected, among the lowest rates for H. pylori in the world.
  • In non-Pakeha communities the rate is higher: Māori, about 35 in every 100 people; Pasifika, about 30 in every 100 people; Asian, about 24 in every 100 people; Indian, about 10 in every 100 people. 
  • These rates can vary considerably (by 20–35%).

What are the symptoms of H. pylori infection?

While most people do not have any symptoms, H. pylori infection can cause:

  • upper abdominal pain
  • heartburn
  • bloating
  • nausea or vomiting
  • poor appetite
  • feeling full after a small meal.
Some warning signs that you need to see a doctor urgently include:
  • dark or tar-coloured poos (a sign of possible bleeding in your stomach)
  • vomiting blood
  • sudden weight loss
  • difficulty swallowing
  • vomiting
  • a family history of stomach cancer
  • symptoms of anaemia such as lightheadedness.

How is H. pylori diagnosed?

Your doctor may test for H. pylori bacteria. This can be done by testing a poo sample or by a blood test. The poo test is more accurate but it can't be done if you have been on recent antibiotics or stomach acid-suppressing medication such as PPIs. Blood testing is not suitable if you have previously been treated for the infection. In some regions of New Zealand, the blood test may not be available.

H. pylori is also commonly diagnosed through taking a biopsy of your stomach during a gastroscopy. A breath test is another method of diagnosis but this is not commonly done in New Zealand.

Who should be tested for H. pylori?

Your doctor may do a test if they believe the chance of infection is high based on your ethnicity and place of birth, or if your symptoms continue despite treatment.

How is H. pylori infection treated?

H. pylori bacteria can be treated by taking 2 antibiotics and another type of medicine called a proton pump inhibitor (PPI). The antibiotics kill the bacteria and the PPIs reduce your stomach acid so the antibiotics can work well. This combination of medicines is often called eradication therapy.

You will need to take eradication therapy for 14 days. It is important to take all the medication exactly as directed and to finish the course.  

Eradication therapy clears H. pylori for 9 out of 10 people if it is taken correctly for the full course. If you don't take the full course of medication, then it will not work so well.

A second course of eradication therapy, using different antibiotics, will usually work if the first course hasn't cleared the infection. Smoking reduces the chance of successful treatment, so it is very important to stop smoking.

Are there any side effects of the treatment?

Up to 3 in 10 people have some side effects when they take eradication therapy. These include indigestion, feeling sick (nausea), taste disturbances, diarrhoea (runny poo) and headaches. These side effects will usually pass after a few days. 

Can I be re-infected?

Once you have had successful treatment of H. pylori, the chance of being re-infected is very low because most infections occur in childhood. It is very rare to get it as an adult. If you have recurrent symptoms it is most likely because the medication to get rid of the bacteria has not worked, rather than you have been re-infected with the bacteria again. 

How can I prevent H. pylori infection?

The exact way that H. pylori bacteria is spread between people is not fully understood, but good hygiene may reduce the spread. This includes:

  • washing your hands with soap and water after going to the toilet and before eating
  • eating only food that has been washed well and cooked properly
  • drinking water only from a clean, safe source.

Learn more

The following links provide further information about H. pylori. Be aware that websites from other countries may have information that differs from New Zealand recommendations.

Helicobacter pylori and stomach pain  Patient Info, UK


  1. The changing face of Helicobacter pylori testing BPAC, NZ, 2014
  2. Helicobacter pylori infection NZ Formulary

Reviewed by

Jeremy Steinberg is a GP with special interests in musculoskeletal medicine, evidence-based medicine and use of ultrasound. He's been reviewing topics for Health Navigator since 2017 and in his spare time loves programming. You can see some of the tools he's developed on his website.

Credits: Health Navigator Editorial Team. Reviewed By: Dr Jeremy Steinberg, FRNZCGP Last reviewed: 17 Apr 2020