Thrice weekly applications of carcinogen 4‐nitroquinoline N‐oxide to rat oral mucosa, induced focal acantholytic dyskeratosis (FAD) in about 50% of the animals. Mucosa overlying bone (palate and attached buccal gingiva) was the area of predilection. The number of oral foci per affected animal ranged between 1 and 3. Histologically, the experimental FAD foci showed all the characteristic features described for human focal acantholytic dyskeratosis. FAD appeared unrelated to malignancy development. It is suggested that FAD represents an induced epithelial differentiation or maturation defect caused by a variety of stimuli among which are chemical carcinogens. The present experimental model seems suitable for further histo‐ and cytopathogenetic st