The oral lesions in 50 habitual snuff-dippers were graded on a four-point scale. The patients' tobacco and drinking habits were studied by means of a questionnaire. From each patient a biopsy was taken for histomorphological and histochemical analysis. A correlation between snuff habits and the clinical degrees was found, as well as between the snuff habits and certain superficial and deeply located cell changes. The incidence of keratinized lesions, sialadenitis and slight dysplasia (based on subjective evaluation under a light microscope) was higher than previously reported. Presence of dysplastic changes could not be predicted by means of the parameters which characterise the snuff habit or from the clinical grade. The histomorphological and histochemical results were interpreted as showing that the mucosa react to snuff inducing hyperplasia in the basal cell layers. In the surface layer indications of lethal damage were found. The overall stromal reaction to snuff was weak. However, the salivary glands and excretory ducts exhibited degenerative changes which were found to be more severe than the pathological changes in the surface epithelium.