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Health condition · Clinically reviewed

Helicobacter pylori, the stomach bug behind most peptic ulcers.

Common, often silent and linked to ulcers, MALT lymphoma and gastric cancer. A short course of treatment, done properly and confirmed cleared, changes long-term risk.

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Why trust this guide

  • 01

    Clinically reviewed

    Written by our editorial team and reviewed by a registered UK clinician before publication.

  • 02

    Sourced from guidance

    Checked against NICE CG184, BSG and Maastricht V/VI consensus you can see at the end.

  • 03

    Current for 2026

    Reflects modern UK practice including 14-day triple therapy, bismuth quadruple regimens and test-of-cure.

Key facts

H. pylori at a glance.

The essentials in plain English - what it is, why it matters and how UK clinicians test and treat it today.

  • What it is

    A gram-negative flagellated bacterium that colonises the gastric mucosa, protected by its own urease from stomach acid.

  • How common

    Around 40 per cent of UK adults carry it, with higher prevalence in older adults and South Asian and African-Caribbean communities.

  • How it spreads

    Faecal-oral and oral-oral transmission, usually acquired in childhood and often lifelong without treatment.

  • Why it matters

    A major cause of peptic ulcers and a WHO Class I carcinogen linked to gastric adenocarcinoma and MALT lymphoma.

  • How it is found

    The urea breath test or stool antigen is first-line, with biopsy-based tests taken during OGD when endoscopy is indicated.

  • How it is treated

    A short course of a PPI plus two antibiotics, followed by test-of-cure four to eight weeks later.

Why this guide matters

A common infection with real long-term consequences.

H. pylori is not just heartburn. It sits behind most peptic ulcers, drives a Class I gastric cancer risk and is genuinely curable when treated properly.

  • It causes most peptic ulcers

    Around 90 per cent of duodenal ulcers and 70 per cent of gastric ulcers are driven by H. pylori. Eradication cuts recurrence dramatically.

  • It raises gastric cancer risk

    WHO classifies H. pylori as a Class I carcinogen for gastric adenocarcinoma and MALT lymphoma. Early eradication can even cure some early MALT lymphomas.

  • Treatment is short and effective

    A one to two week combination of a PPI and two antibiotics clears most cases, with a simple breath or stool test confirming success.

How the diagnosis is made

From first symptoms to confirmed cure.

The steps a UK GP or gastroenterologist will normally follow, in order - so you know what to expect and why each test matters.

  1. 01

    Assessing

    Symptom review and risk

    Dyspepsia, epigastric pain, nausea, heartburn or bloating, plus family history, ethnicity and prior peptic ulcer disease.

  2. 02

    Assessing

    Rule out red flags

    Weight loss, dysphagia, iron-deficiency anaemia, vomiting or a mass warrant urgent gastroenterology, not just a breath test.

  3. 03

    Assessing

    Stop PPIs and antibiotics first

    PPIs are stopped two weeks and antibiotics four weeks before testing, otherwise a truly active infection can look negative.

  4. 04

    Confirming

    Urea breath test (13C-UBT)

    The non-invasive gold standard for active infection, offered in primary care under NICE CG184.

  5. 05

    Confirming

    Stool antigen test

    An accurate alternative when the breath test is not available, and useful in children and older adults.

  6. 06

    Confirming

    Biopsy at OGD when indicated

    Rapid urease (CLO), histology and occasionally culture during gastroscopy for red flags, treatment failure or ulcer disease.

  7. 07

    Retesting

    Test-of-cure at 4 to 8 weeks

    A repeat urea breath test or stool antigen confirms the infection has actually cleared before you draw a line under it.

Typical timeline: first test to confirmed clearance in around two to three months.

Symptoms

What H. pylori actually feels like.

Most people notice nothing. Those who do get a familiar mix of dyspepsia, epigastric pain and reflux - occasionally with more serious features that change the plan.

  • Often silent

    The majority of people with H. pylori have no symptoms at all, and are found incidentally or through targeted testing.

  • Epigastric pain

    A gnawing or burning discomfort in the upper abdomen, sometimes worse when hungry and eased by food or antacids.

  • Dyspepsia and bloating

    Indigestion, early fullness and bloating after meals, often labelled functional until infection is excluded.

  • Nausea and reflux

    Nausea, occasional vomiting and heartburn overlap with reflux disease and complicate the picture.

  • Peptic ulcer symptoms

    Duodenal or gastric ulcer pain, night-time waking with pain, or bleeding presenting as melaena or coffee-ground vomiting.

  • Iron-deficiency anaemia

    Unexplained iron deficiency, especially in younger adults, can be driven by chronic H. pylori gastritis.

  • Idiopathic thrombocytopenia

    ITP with an unexplained low platelet count sometimes improves with H. pylori eradication.

  • Red flag - bleeding or weight loss

    Melaena, haematemesis, dysphagia, unintentional weight loss or a mass need urgent OGD, not primary-care testing alone.

Treatment

How H. pylori is treated in the UK.

Short combination courses of a PPI plus two antibiotics, chosen to work around allergies and resistance, and always followed by test-of-cure.

  • First-line triple therapy

    A PPI with amoxicillin 1 g twice daily and clarithromycin 500 mg twice daily, typically for 14 days to improve eradication.

  • Penicillin-allergic option

    A PPI with metronidazole and clarithromycin when amoxicillin cannot be used, at similar doses and duration.

  • Second-line triple therapy

    After first-line failure, a PPI with amoxicillin and metronidazole, avoiding the antibiotic used first time round.

  • Bismuth quadruple therapy

    PPI plus bismuth subcitrate, tetracycline and metronidazole (Pylera) for 10 days, used third-line or where resistance is likely.

  • Levofloxacin-based rescue

    A selective salvage regimen for refractory infection, tempered by rising quinolone resistance across the UK.

  • Vonoprazan-based regimens

    Emerging potassium-competitive acid blocker combinations, not currently licensed in the UK but discussed in international guidance.

  • Test-of-cure

    A urea breath test or stool antigen four to eight weeks after finishing therapy, off PPIs and antibiotics, to confirm eradication.

  • Specialist gastroenterology

    MDT input for complex, refractory, MALT lymphoma or gastric cancer surveillance cases, coordinated with endoscopy services.

What this guide is based on

The sources behind every claim on this page.

UK national guidance, specialist society standards and international consensus, current at the time of last review.

Key references

Guidelines and standards we relied on.

A quiet reminder

This guide is for information, not medical advice.

Your GP or gastroenterologist knows your history and medications and can tell you which parts apply to you. If in doubt, get seen.

  • NICE. Gastro-oesophageal reflux disease and dyspepsia in adults: investigation and management (CG184).

  • British Society of Gastroenterology (BSG). Guidance on Helicobacter pylori testing and eradication.

  • Maastricht V/Florence and Maastricht VI consensus reports on the management of Helicobacter pylori infection.

  • IARC/WHO. Helicobacter pylori classified as a Class I carcinogen.

Red flags

When dyspepsia needs urgent attention.

Most H. pylori is managed in primary care. These are the situations where a straight breath test is not enough and specialist review is needed.

  • Gastrointestinal bleeding

    Melaena, haematemesis or coffee-ground vomiting is an emergency, needing hospital assessment and urgent OGD.

  • Unintentional weight loss

    New dyspepsia with weight loss, especially over 55, warrants urgent upper GI referral rather than a trial of eradication.

  • Dysphagia or persistent vomiting

    Difficulty swallowing or repeated vomiting suggests obstruction or malignancy and needs urgent endoscopy.

  • Iron-deficiency anaemia

    Unexplained iron deficiency in a middle-aged or older adult needs both upper and lower GI investigation, not just a breath test.

  • Epigastric mass

    A palpable upper abdominal mass is a red flag for gastric cancer and needs urgent imaging and gastroenterology review.

  • Family history of gastric cancer

    A first-degree relative with gastric cancer shifts the threshold for OGD and eradication, particularly in high-risk ethnic groups.

  • Known peptic ulcer disease

    A previous duodenal or gastric ulcer means eradication is not optional, and confirmed test-of-cure really matters.

  • Long-term NSAID or aspirin use

    Chronic NSAID users with dyspepsia need testing and gastroprotection, since the ulcer risk compounds.

  • Refractory or recurrent infection

    Failure of two courses of eradication is a signal for specialist input, susceptibility testing where available and quadruple therapy.

Living with it

A treatable infection, if you finish the course.

Four practical things that decide whether eradication actually works - completing therapy, tolerating side effects, retesting and reducing future exposure.

A quiet reminder

Symptoms improving is not the same as cure.

Feeling better is a good sign, but only a test-of-cure tells you the infection has truly cleared.

  1. 01 Finish

    Complete the whole course

    Even a few missed doses drop eradication rates and drive resistance. Take every tablet, every day, until the pack is empty.

  2. 02 Side effects

    Expect some rough days

    Metallic taste, mild nausea, loose stools and a furred tongue are common. Persistent vomiting or a rash needs a call to your GP.

  3. 03 Retest

    Come back for test-of-cure

    Symptoms settling is not the same as the infection clearing. A breath test or stool antigen four to eight weeks later closes the loop.

  4. 04 Prevent

    Reduce future risk

    Hand hygiene and food and water safety cut re-exposure, especially when travelling or living in higher-prevalence settings.

Frequently asked

Everything we get asked about H. pylori.

Quick answers on testing, eradication, penicillin allergy and why test-of-cure matters.

  • What is Helicobacter pylori?

    H. pylori is a gram-negative flagellated bacterium that colonises the lining of the stomach. It survives stomach acid using an enzyme called urease and is one of the most common chronic bacterial infections in the world, carried by around 40 per cent of UK adults.

  • How did I catch it?

    H. pylori is spread by faecal-oral and oral-oral routes, usually within families and usually in childhood. It is not really a food-poisoning-style acute infection, more a long-term coloniser you may have carried for years without knowing.

  • Do I need treatment if I have no symptoms?

    Not always. Eradication is clearly recommended when there is peptic ulcer disease, MALT lymphoma, unexplained iron-deficiency anaemia, ITP or a strong family history of gastric cancer. In fully asymptomatic people without risk factors the decision is individualised with your GP or gastroenterologist.

  • Which test is best?

    For active infection, the 13C urea breath test is the non-invasive gold standard. Stool antigen is a good alternative. Serology tells you about past exposure but is not reliable for current infection. Biopsy-based tests (rapid urease, histology, culture) are taken during OGD when endoscopy is already indicated.

  • What does treatment involve?

    A short course, typically 7 to 14 days, of a proton pump inhibitor plus two antibiotics. First-line in the UK is a PPI with amoxicillin and clarithromycin, or a PPI with metronidazole and clarithromycin if you are penicillin-allergic. Bismuth quadruple therapy is used third-line or where resistance is a concern.

  • Why do I need a test-of-cure?

    Symptoms can improve while the bacterium is still present, and untreated infection keeps the risk of ulcer disease and gastric cancer in place. A repeat urea breath test or stool antigen four to eight weeks after finishing treatment, off PPIs and antibiotics, confirms the infection has actually cleared.

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