The presented manual covers etiopathogenesis, clinical course, morphology, diagnostic measures and treatment of various pathologies of the oral and lip mucosa, their prevention. Various diseases (infectious, traumatic, allergic), changes in the above structures in the pathology of internal organs, dermatoses, diseases of the hematopoietic organs are covered. Pre-neoplastic and tumor diseases, epithelial dysplasias, occupational pathology are considered separately. The book is aimed at dentists and dermatologists.