Helicobacter pylori (Fig. 1), previously called Campylobacter pylori, is a gram-negative, microaerophilic bacterium found usually in the stomach. It was identified in 1982 by two Australian who found it in a patient with chronic gastritis and gastric ulcers, conditions not previously thought to have a bacterial aetiology. H. pylori is also linked to the development of duodenal ulcers and stomach cancer. It is present in the stomach of 50% of the world’s population and asymptomatic in over 80% of those infected. The standard first-line therapy to eradicate H. pylori, is the so-called triple therapy consisting of proton pump inhibitors (PPI), mainly omeprazole, along with the antibiotics clarithromycin and amoxicillin. Variations on the triple therapy have been developed over the years, using a different PPI, or replacing amoxicillin with metronidazole for those with an allergy to penicillin. Due to antibiotic-resistant bacteria, an additional round of antibiotic therapy, the quadruple therapy, consisting of a PPI, a bismuth colloid, metronidazole and tetracyclines, has been developed.