One of the important factors influencing the development of tumors are dietary habits. It is believed that increased consumption of fatty and protein foods, alcoholic beverages, irregular meals contribute to the development of stomach cancer. On the contrary, the presence in the diet of a sufficient amount of plant foods: vegetables, herbs, fruits, milk, selenium can provide and enhance the body's defense response. The most important tool in the hands of a primary health care worker should be an algorithm for tactical management of a patient in case of a suspected malignant neoplasm of one or another localization, and it is then that the desired social effect will be achieved even with the low information content of questionnaire screening. The article analyzes the identification of patients with precancerous diseases of the gastrointestinal tract, as well as the results of preventive examinations for malignant neoplasms. The results of the analysis showed that after the timely detection of precancerous diseases and their treatment, as well as in-depth preventive examinations, the identification of patients in the early stages of the process improved significantly.