The article is devoted to the study of the diagnostic effectiveness of using magnifying chromoendoscopy when examining the oral cavity in patients with a gastroenterological profile with extra-esophageal manifestations of reflux disease. Pathologies of the oral cavity are often one of the additional symptoms, according to the Montreal Consensus and classification of gastroesophageal reflux disease (GERD). Barrett’s esophagus is a serious complication of GERD, in which a cylindrical epithelium with intestinal metaplasia is found in the epithelial lining of the mucous membrane of the esophagus, which is a marker of this disease often in combination with dysplasia instead of squamous stratified non-keratinized epithelium. The relevance is due to the fact that this disease is considered as a precancerous condition and is associated with an increased risk of developing adenocarcinoma of the lower third of the esophagus. In this regard, timely diagnosis of Barrett’s esophagus and monitoring of these patients will improve the prognosis of the disease and reduce the frequency of deaths.