Abstract
. Leukoplakia is an orogenesis of the oral mucosa and red karma of the lips, accompanied by inflammation, which occurs, as a rule, in response mainly to chronic exogenous irritation, without denying the influence of endogenous factors. Clinically, there are flat, verricose, erosive-ulcerative, smokers' leukoplakia (Toppeiner), simple and mild forms of leukoplakia. Leukoplakia of the oral mucosa belongs to facultative precancers, the degree of probability and frequency of malignancy of which are not clearly defined and according to cancer studies vary from 12 to 25%.