This document discusses various types of red and white lesions that can occur in the oral mucosa. It describes hereditary lesions including leukodema, white sponge nevus, and hereditary benign intraepithelial dyskeratosis. It also covers reactive/inflammatory lesions such as frictional keratosis. Infectious lesions covered include oral hairy leukoplakia caused by Epstein-Barr virus and various forms of oral candidiasis. Idiopathic "true" leukoplakia and erythroplakia are also discussed. Treatment options are provided for many of the conditions.