Helicobacter pylori is a gram-negative bacterium that is quite common among the world’s population. To date, the pathogenetic mechanisms of the bacterium’s influence on gastroduodenal ulcers and gastric cancer have been most deeply studied. However, there is a growing number of sources devoted to the association of Helicobacter pylori with the occurrence of many extra-gastric diseases. These data are quite contradictory and controversial. Given the close anatomical and functional relationship of the digestive system (digestive tract and digestive glands), it is quite natural that the bacterium Helicobacter pylori, which persists in the antrum of the stomach, has a pathological effect on this system, causing the development of a number of diseases and their complications. The purpose of this study is to analyze the current state of the problem of the role of Helicobacter pylori in the pathogenesis of diseases of the digestive system. This review presents the latest data on the pathogenetic mechanisms of gastroduodenal ulcer and gastric cancer. The persistence of the bacterium in the pancreatic-biliary system causes cholecystitis, and gallstone disease, including cholelithiasis, acute and chronic pancreatic inflammation, non-alcoholic fatty liver disease, and liver cirrhosis. Various mechanisms of carcinogenesis of tumors of the liver, gallbladder and bile ducts, and pancreas, in which Helicobacter pylori is directly involved, are highlighted. Further study of the role of the bacterium as a predictor of the development of diseases of the digestive system and their complications is promising and relevant