Helicobacter pylori (H. pylori) is one of the most famous bacteria in the world, a Gram-negative bacillus that is curved in an inverse S-shape or curved arc, and mainly parasitizes the mucous membranes in the vicinity of the gastric pylorus and gastric sinus. Research on it has endured since its discovery. On October 3, 2005, Australian scientists Barry J. Marshall and J. Robin Warren were awarded the Nobel Prize in Physiology and Medicine. for their “discovery of the bacterium Helicobacter pylori and the role it plays in diseases such as gastritis and gastric ulcers. In 1994, H. pylori was classified as a Class I carcinogen by the WHO. The prevalence of H. pylori infection in China is high, ranging from 40% to 60%. Outpatient clinics often encounter patients inquiring about infections in children and infections in the elderly. The Fifth National Consensus on the Diagnosis and Treatment of Helicobacter pylori issued in 2016 gives a clear direction for diagnosis and treatment: What about children infected with Helicobacter pylori? Routine H. pylori testing is not recommended for children under 14 years of age. H. pylori testing and treatment is recommended for children with peptic ulcers, and H. pylori testing and treatment is recommended for children who undergo endoscopy for dyspepsia. How are elderly patients managed? Elderly patients (age >70 years) are at increased risk of adverse drug reactions with H. pylori eradication therapy; therefore, H. pylori eradication therapy in the elderly should be individualized with a comprehensive benefit-risk assessment.