Helicobacter pylori (H. pylori), a gram-negative bacterium that colonizes the human stomach, has been evolving with humans for tens of thousands of years. Substantial evidence supports a central role for H. pylori in the pathogenesis of upper gastrointestinal diseases, including peptic ulcer and non-cardia gastric cancer. Unlike other developed countries, gastric cancer burden remains high in Japan, where it is the second leading cause of cancer deaths, accounting for annual deaths of approximately 50,000. The reason for the lingering high gastric cancer incidence is manifold, but a high prevalence of H. pylori infection, reportedly as high as 80% among Japanese adults over 40 years old in a 1982 study by Asaka et al, appears to be the major contributor. Currently approximately 40% of the Japanese adult population are estimated to be infected with H. pylori .
since 2013 in Japan， and the number of H． pylori eradication has rapidly increased． Under such circumstances， JSHＲ has made the third revision to the“Guidelines for diagnosis and treatment of H． pylori infection”for the first time in 7 years． Methods The Guideline Committee held 10 meetings． Articles published between the establishment of the 2009 Guidelines and March 2016 were reviewed and classified according to the evidence level; the statements were revised on the basis of this review． After inviting public comments， the revised statements were finalized using the Delphi method． Ｒesults There was no change in the basic policy that H． pylori infectious disease is an indication for eradication． Other diseases presumed to be associated with H． pylori infection were added as indications．
Currently in Japan, Helicobacter pylori infection mainly occurs in infancy, and the main route of infection is family infection.
In Japan, the cause of most gastric cancer cases is Helicobacter pylori infection. Patients who are not infected with Helicobacter pylori have a very low risk of gastric cancer. Helicobacter pylori infection increases the risk of undifferentiated gastric cancer and also increases the risk of differentiated gastric cancer.
Eradication H.pylori can reduce the risk of gastric cancer. Early eradication of infection is more effective in preventing gastric cancer.