AbstractIn this study scanning electron microscopy is used to document the surface features of superficial cells of buccal mucosa and to evaluate the usefulness of examination of oral swabs in monitoring radiotherapy in the mouth. Biopsy samples of buccal mucosa from 5 patients and oral swabs from 8 volunteers and 7 patients were examined.The surfaces of the buccal epithelial cells in healthy subjects were found to have a variable morphology. Cells nearer the surface showed a pattern of parallel microplicae or microvilli, while less mature cells showed more complex patterns such as irregular microplicae, microplicae forming a maze‐like pattern or a mixture of microplicae and microvilli. Adjacent celis frequently exhibited different patterns, and superficial and deep surfaces of the same cell consistently had different appearances. In particular, all the appearances described by Robertson et al.: J. Submicrosc. Cytol.,19:515–521, 1987, following radiotherapy were noted in the normal subjects in the present study.The findings emphasize the need for caution in attributing particular cell‐surface patterns to the effect of specific doses of radiation and suggest that scanning electron microscopy of oral swabs is unlikely to be useful in monitoring the progress of radiotherapy. © 1994 Wiley‐L