H. pylori is a harmful rather than a beneficial Gram-negative bacterium to humans, and it is the only pathogenic bacterium known to survive and colonize the stomach. Some studies have pointed out that H. pylori is a Gram-negative bacillus that requires particularly demanding conditions for survival, and it often survives in the pyloric region of the human stomach. It is harmful to human health, and it is not only highly contagious, but also has a long incubation time. According to statistics, more than half of the world’s population has been infected by H. pylori, and in a small number of countries, up to 90% of people have been infected with this germ of. In general, people are usually infected at an early age, and it can reach about 50% in people under 5 years old. This bacterial infection first causes chronic gastritis and can lead to gastric and duodenal ulcers and possibly back to gastric cancer via the atrophic gastritis, intestinal metaplasia, and heteroplasia pathways. It has been shown that the incidence of atrophic gastritis and gastric cancer is higher in people who are infected with H. pylori for the first time and at an earlier age, and there is a parallel relationship between H. pylori infection and the mortality rate of gastric cancer. In conclusion, H. pylori is a harmful germ rather than a beneficial one, which can cause many chronic diseases such as gastritis, peptic ulcer or lymphoproliferative gastric lymphoma, and is also a predisposing factor for gastric cancer.