Helicobacter Pylori

Helicobacter pylori (commonly written as H. pylori) is a bacterium that lives within the stomach’s lining. It is the most widespread bacterial infection in the world, estimated to affect around half the global population. In Australia, rates have fallen considerably over recent decades, particularly in younger people, though approximately 40% of Australians aged over 60 are thought to carry the infection. It is more prevalent in some communities, including Aboriginal and Torres Strait Islander peoples, as well as in people from Middle Eastern, Asian and Eastern European backgrounds. Infection rates for men and women are similar.

For many people, an H. pylori infection causes no symptoms at all and goes completely unnoticed. However, if left undetected and untreated, it can lead to more serious conditions including peptic ulcers and, in a small number of cases, stomach cancer. Understanding H. pylori is an important step in protecting your digestive health.

How does Helicobacter Pylori (H. pylori) spread?

The precise route of transmission is not fully understood. Most people are infected during childhood through close contact with other people, and adult infection is uncommon. The bacterium is thought to spread through shared food or eating utensils, contact with contaminated water, or exposure to the stool or vomit of an infected person. It has also been detected in the saliva of some infected individuals, suggesting transmission through direct contact with saliva is possible. Research has not identified any animals (household pets or livestock), as a known source of infection.

Improvements in household hygiene standards throughout the twentieth century are widely credited with the significant decline in H. pylori rates seen across western countries. While no vaccine currently exists, researchers are actively working to develop one. Practical measures to reduce the risk of infection include washing hands thoroughly with soap and water before eating and after using the bathroom, eating well-prepared food from reliable sources, and drinking water from a clean, safe supply.

What conditions can Helicobacter Pylori (H. pylori) cause?

The majority of people who carry H. pylori will never experience symptoms or develop disease related to the infection. When complications do arise, however, they can be significant.

Peptic ulcers

A peptic ulcer is a sore or break in the inner lining of the stomach (a gastric ulcer) or the upper part of the small bowel, known as the duodenum (a duodenal ulcer). H. pylori is the leading cause of peptic ulcers worldwide, responsible for approximately 70% of gastric ulcers and 90% of duodenal ulcers. Most remaining cases are associated with regular use of non-steroidal anti-inflammatory medications (NSAIDs) such as ibuprofen, or low-dose aspirin. For someone carrying H. pylori, the lifetime risk of developing an ulcer is estimated at between 10 and 20%.

Modern medications are effective at healing the majority of peptic ulcers. However, if the underlying H. pylori infection is not addressed, there is a very high likelihood that the ulcer will return. Successfully treating the infection substantially reduces the risk of recurrence. It is worth noting that paracetamol does not cause ulcers and is considered a safe pain relief alternative for patients with a history of peptic ulcer disease.

Stomach cancer

Helicobacter Pylori or H. pylori infection is associated with an increased risk of certain stomach cancers, including adenocarcinoma and a rarer form known as MALT lymphoma. The overall risk remains low as only around 1% of people with H. pylori will develop stomach cancer, and the condition is uncommon in those under 60 years of age. Risk is elevated in people with a family history of gastric cancer.

Gastritis

H. pylori frequently causes inflammation of the stomach lining, referred to as gastritis. This inflammation typically produces no noticeable symptoms. While treating the infection allows the inflammation to resolve, a small number of patients develop changes to the stomach lining cells, known as intestinal metaplasia, which may require longer-term medical follow-up.

Non-ulcer Dyspepsia

Dyspepsia, more commonly known as indigestion, describes persistent discomfort or pain in the upper abdomen. Most people with dyspepsia do not have an ulcer; they have what is termed non-ulcer dyspepsia. This is a common condition with a range of contributing factors. Some patients with non-ulcer dyspepsia do carry H. pylori, though treating the infection does not always resolve the digestive symptoms.

Symptoms of Helicobacter Pylori (H. pylori) Infection

Most people with H. pylori have no symptoms. When symptoms do occur, they may include a burning or gnawing sensation in the upper abdomen, nausea, bloating, burping, indigestion, or a reduced appetite. If you vomit blood or notice dark or tar-coloured stools, you should seek urgent medical attention, as these may indicate a bleeding ulcer.

How is Helicobacter Pylori (H. pylori) diagnosed?

There are several reliable and straightforward tests available to detect H. pylori. Your doctor will advise which test is most appropriate based on your individual circumstances.

Breath Test

The urea breath test is one of the most accurate and practical ways to confirm whether an active H. pylori infection is present. During the test, you swallow a preparation containing a special form of carbon, and a breath sample is then analysed for signs of the bacteria. The test is safe, non-invasive and quick, and it is particularly useful both for confirming a current infection and for checking whether treatment has been successful. Results are typically negative within one month of completing effective treatment. It is important to note that accuracy can be reduced by recent antibiotic use or certain ulcer-healing medications, so your doctor may ask you to pause these before testing.

Blood Test

A blood test can detect antibodies to H. pylori, which indicate whether the body has encountered the infection at some point. While useful for identifying whether infection has occurred, blood testing is not well suited to confirming whether treatment has worked, because antibodies can remain detectable in the bloodstream for many months or even years after the infection has been cleared.

Endoscopy (Gastroscopy)

Helicobacter Pylori (H. pylori) can also be identified during an endoscopy (also known as a gastroscopy), a procedure in which a thin, flexible tube with a camera is passed through the mouth into the stomach. Small tissue samples (biopsies) can be taken during the procedure and tested for the presence of the bacteria. Endoscopy may be recommended when there is a family history of gastric cancer or when specific symptoms warrant closer examination of the stomach. A false-negative result is possible if antibiotics or ulcer medications have been taken recently.

Stool Antigen Test

A sample of stool (bowel motion) can be tested in a laboratory for proteins produced by H. pylori. This method is commonly used to check for infection in children.

Who should be tested for Helicobacter Pylori (H. pylori)?

Testing is generally recommended for the following groups. Anyone who has an active or previous peptic ulcer should be tested and treated if H. pylori is found, including those whose ulcers developed while using aspirin or anti-inflammatory medications. People with persistent non-ulcer dyspepsia may also benefit from testing, as eradicating H. pylori can reduce the long-term risk of ulcers and stomach cancer, even if it does not always resolve symptoms directly. Testing is also considered for those with a family history of stomach cancer, and for people who have previously undergone treatment for H. pylori to confirm that the infection has been successfully cleared.

Your gastroenterologist will assess your individual history and circumstances to determine whether testing is appropriate for you.

How is Helicobacter Pylori (H. pylori) treated?

Treatment is recommended for people who have H. pylori associated gastritis, peptic ulcers or other complications. Treating the infection supports ulcer healing, reduces the risk of recurrence and lowers the risk of gastric cancer.

Because the infection does not respond reliably to a single medication, treatment involves a combination of at least three drugs taken together. This typically consists of an acid-suppressing medication alongside two antibiotics. The most widely used first-line regimen in Australia is a combination of esomeprazole with amoxicillin and clarithromycin#, usually taken over seven days. An alternative regimen is available for patients who cannot take penicillin-based antibiotics.

When taken correctly and consistently, the most effective treatment combinations achieve eradication in 80 to 90% of cases. Adherence to the full course is essential, as incomplete treatment significantly reduces the chances of success.

Side effects can occur with any of these medications and may include nausea, changes to taste, diarrhoea or skin rashes. Some patients taking certain antibiotics such as metronidazole or tinidazole experience an unpleasant reaction to alcohol, and abstinence from alcohol during the course of treatment is advised. Serious side effects are rare but can include bowel infection or severe allergic reactions. It is important to inform your doctor of any prior reactions to antibiotics before beginning treatment.

If the initial course of treatment does not eradicate the infection, which occurs in up to 10% of cases, a specialist gastroenterologist can recommend an alternative medication combination and guide further management.

Confirming that Helicobacter Pylori treatment has worked

Following completion of treatment, a confirmatory test is generally recommended to verify that the infection has been successfully cleared. A breath test performed at least four weeks after the course of treatment is complete is the standard approach. To ensure an accurate result, anti-ulcer medications are usually discontinued for at least two weeks before the test. If an endoscopy is already planned, testing for H. pylori can be incorporated into that procedure.

If the infection has not been eradicated, your doctor will discuss alternative treatment options.

Is Helicobacter Pylori re-infection likely?

Once H. pylori has been successfully eradicated, the risk of becoming re-infected is very low, estimated at less than 1% per year. As most infections are acquired during childhood, re-infection in adulthood is uncommon.

Do family members need to be tested?

Routine testing of family members is not generally recommended. In certain circumstances, your doctor may consider this appropriate and can advise accordingly during your consultation.

When to seek medical advice

If you are experiencing persistent upper abdominal discomfort, unexplained nausea, or symptoms that are affecting your daily life, it is worth discussing these with your doctor. Early assessment allows for accurate diagnosis and, where H. pylori is identified, timely and effective treatment.

Queensland Gastroenterology offers specialist assessment, testing and management of Helicobacter Pylori (H. pylori) and its associated conditions.

If you have received a referral to see one of our doctors, you can request an appointment, or contact our rooms directly on (07) 3321 1500.

This information has been sourced and adapted from education resources developed by the Gastroenterological Society of Australia (GESA) and Health Direct (Australia).

# Recommendations current at time of publishing
Last reviewed 4/3/2026