Every year the prevalence of oncological diseases of the oral cavity is steadily increasing, the reason for this are the numerous risk factors present in everyday life. Unfortunately, about 55 % of cases of oncology in the oral cavity are diagnosed at late stages, when it is almost impossible to achieve positive outcomes of the disease. Often, this is due to the low oncological alertness of dentists, as well as the insufficient volume of diagnostic measures in the early stages of the disease. The relevance of the problem of early diagnosis of oncological diseases of the oral mucosa is due to their extensive geographical distribution and an increase in the frequency of occurrence. This problem arises due to many factors, in particular, when patients do not see a doctor in time, as well as when they visit the dentist irregularly. Oral cancer is one of the most common malignant neoplasms worldwide. Despite the fact that early diagnosis is relatively simple, patients see an oncologist already at advanced stages of the disease. This article will present clinical cases that will be necessary for the formation of oncological alertness by general practitioners, therapists, surgeons and orthopedists on an outpatient basis.