The condition of the protective barrier of the stomach in patients with duodenal ulcer associated and non-associated with H. pylori infection has been studied. The state of gastric mucosal barrier was studied in 72 patients with peptic ulcer disease association with H. pylori and 26 patients without H. pylori by determining the content of insoluble glycoproteins and its fractions in the basal portion of the gastric juice. In a comparative perspective the state of these indicators were studied depending on the association with H. pylori and the severity of the disease. In patients with H. pylori, damages of protective mucus barrier are characterized by the significant shortage of fucose, which is considered to be the main component of the insoluble glycoproteins. In patients without H. pylori, status of mucosal barrier is characterized by uniform and less significant reduction in the content of fractions of insoluble glycoproteins. In this patients the reduction of insoluble glycoproteins is not dependent on the frequency of exacerbation. The content of fucose in the mucous gel of gastric juice is a diagnostic criterion for determining the frequency of recurrence of the disease in patients with H. pylori infection., Abdujalol Vahabovich Yakubov, Nargiza Ihsanovna Pulatova, and Literatura