H. pylori infection is highly prevalent in the Asia-Pacifi c region and is a major cause of peptic ulcer disease, also plays an important role in gastric carcinogenesis. Our treatment guidelines recommend H. pylori eradication in duodenal ulcer (DU), gastric ulcer (GU) and erosive gastritis but not in non-ulcer dyspepsia (NUD). Test-and-treat strategy is not widely employed in Thailand because of high prevalence of infection, high cost of treatment and high antibiotic resistance rate. NUD is the most common cause of dyspepsia in the community and endoscopy-based population. H. pylori eradication defi nitely benefi ts patients with peptic ulcer disease (PUD), both DU and GU which account for less than 10% in both investigated and uninvestigated dyspepsia. However, its role in NUD remains controversial and is considered on a case-by-case basis. H. pylori eradication potentially removes risks for subsequent development of PUD and gastric cancer. With the concern of H. pylori-gastric cancer link, mass eradication may be benefi cial in a high gastric cancer area such as in Japan, China and Korea. Thailand is however, considered to be a country of low prevalence of gastric cancer in spite of high prevalence of H. pylori infection. H. pylori genotypes in Thailand differ from those in countries with high prevalence of gastric cancer. Besides, the inter-relationships among bacterial virulence factors, host factors and environmental factors are important determining factors of disease outcomes. Standard triple therapy consisting of a proton pump inhibitor, clarithromycin and amoxicillin is widely used in eradication of H. pylori in both complicated and uncomplicated PUD, erosive gastritis and in some NUD patients. H. pylori screening and therapy in patients on long-term NSAIDs or family members of gastric cancer are not recommended. The standard triple therapy yields eradication rate about 70%-80%. Metronidazole (MTZ) is not widely used because of high resistance approaching 50% and unpleasant side effects. Quadruple therapy containing bismuth compound results in eradication rate over 80% and could be used in combination with MTZ as fi rst line therapy to overcome MTZ resistance and may be used as salvage therapy after triple eradication failure.