Aim: To study in rats the effects of exposure to tobacco and alcohol on the mucosa of the tongue and pharynx.Material and methods: Forty adult Wistar rats were allocated into four groups of 10 animals each: GI (control), food and water "ad libitum"; GII (alcohol), 30% of ethanol diluted in drinking water and food "ad libitum"; GIII (tobacco), exposure to the smoke of 10 cigarettes/day, food and water "ad libitum"; GIV (alcohol and tobacco), simultaneous exposure to both agents. After 260 days, the animals were sacrificed. Tongue and pharynx were removed for histopathological analysis.Results: GI had the lowest tongue and pharynx histological scores. In GII, GIII, and GIV tongue samples revealed: apical cell hyperplasia (GII: 60%, GIII: 30%, GIV: 20%), basal cell hyperplasia (GII: 60%, GIII: 40%), hyperkeratosis (GII: 70%, GIII: 30%, GIV: 30%), dysplasia (GII: 60%, GIII: 60%, GIV: 50%), and apoptosis (GII: 60%, GIII: 40%, GIV: 60%). Pharynx samples revealed: apical cell hyperplasia (GII: 40%, GIII: 30%, GIV: 70%), basal cell hyperplasia (GII: 30%, GIII: 40%, GIV: 40%), hyperkeratosis (GII: 50%, GIII: 80%, GIV: 40%), and dysplasia (GII: 50%, GIII: 80%, GIV: 50%). Carcinoma in situ was detected in both sites.Conclusions: Alcohol and tobacco led to significant tongue and pharyngeal lesions that ranged from benign events to severe dysplasia. These findings confirm the deleterious effects of alcohol and tobacco on the airway mucosa.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)