The problems of diagnosis, treatment and prevention of diseases of the oral mucosa and the red lip border remain one of the most relevant in modern dentistry. The review analyzes clinical and epidemiological studies of pathological conditions on the oral and lip mucosa. The role of risk factors in the occurrence of certain nosological groups of diseases of the mouth and lips is indicated according to the literature. The relationship between age-related regenerative features of the oral mucosa, as well as the presence of somatic diseases and the development of oral pathology is shown. The influence of local risk factors on the occurrence of lesions on the mucous membrane of the mouth and lips is described, among which injuries with dentures and poor oral hygiene come to the fore. The significance of social and behavioral determinants, such as smoking and alcohol consumption, in the occurrence of precancerous processes on the mucous membrane of the mouth and lips is reflected. Changes in the structure of the mucous membrane of the mouth and lips depending on the age and sex characteristics of patients are highlighted. In young people, glossitis (folded tongue, geographic tongue) and cheilitis (chronic lip cracks, meteorological cheilitis) occupied the leading positions among oral lesions. A high proportion of lesions in middle-aged people accounted for precancerous (lichen planus, leukoplakia) and neurogenic (glossalgia) processes. Prosthetic stomatitis and dermatosis (erythema multiforme exudative, lupus erythematosus, lichen planus) were more often noted in elderly, senile patients and centenarians. The importance of studying the incidence structure of the oral mucosa and lips in each age and sex group is emphasized in order to identify and assess the impact of potential risk factors, as well as to develop and improve regional preventive programs for maintaining dental health.