Helicobacter pylori (H. pylori) is a type of bacteria that infects the stomach and the upper part of the small intestine.

It is one of the most common causes of peptic ulcer disease, with 95% of duodenal and 70–80% of gastric ulcers associated with it.

H. pylori is a spiral-shaped bacterium that can survive in the acidic environment of the stomach by producing an enzyme called urease, which converts urea to ammonia, neutralizing the stomach acid. This allows the bacteria to live and multiply in the stomach lining, leading to inflammation and damage.

Testing for h. Pylori
  • Patients with uncomplicated dyspepsia

  • Patients who are unresponsive to lifestyle changes and antacids, following a single one month treatment course with a proton pump inhibitor

  • High risk people i.e. older people, individuals of North African ethnicity, or those living in high risk areas

  • Patients with unexplained iron-deficiency anaemia after endoscopic investigation has determined there is no malignancy, and other causes have been investigated.


H.Pylori Tests
  • The urea (13C) breath test
  • Stool Helicobacter Antigen Test (SAT),
  • Laboratory-based serology

These tests should not be done within 2 weeks of having a proton pump inhibitor or within 4 weeks of antibacterial treatment, as this can lead to false negatives.

Pharmacological Treatment

No Penicillin Allergy
7 day treatment


First line: 
Amoxicillin + Clarithromycin or Metronidazole + PPI

Second line:
Amoxicillin + Clarithromycin or Metronidazole (whichever was not initially used) + PPI

Second line (alternative):
Clarithromycin + Metronidazole + Amoxicillin + Tertracycline (or Levofloxacin) +PPI

Note: Tetracycline and levofloxacin are both unlicensed use

Penicillin Allergy
7 day treatment

First line:

Clarithromycin+ Metronidazole + PPI


First line (Alternative)
PPI + bismuth subsalicylate + metronidazole + tetracycline 

Second Line:
PPI + metronidazole, + levofloxacin (if not already treated with fluoroquinolone) 

Second line (alternative)
PPI + bismuth subsalicylate + metronidazole + tetracycline. 

Note: Tetracycline and levofloxacin are both unlicensed use