The colour of a lesion is due to its nature and to its histological substratum. In order to ease diagnosis, oral cavity lesions have been classified according to their colour in: white, red, white and red, bluish and/or purple, brown, grey and/or black lesions. To the best of our knowledge, there is no such a classification for yellow lesions. So, a suggestion for a classification of yellowish lesions according to their semiology is made with the following headings: diffuse macular lesions, papular, hypertrophic, or pustular lesions, together with cysts and nodes. This interpretation of the lesions by its colour is the first step to diagnosis. It should be taken into account that, as happens with any other classification, the yellowish group of lesions includes items with different prognosis as well as possible markers of systemic disorders.