The Cytobrush has been used frequently in cervical cytology, but as yet its value in oral exfoliative cytology has not been assessed. A study was undertaken to compare the efficiency of the Cytobrush with that of the wooden tongue spatula. For 26 patients, two smears were collected from clinically normal mucosa from four sites in the oral cavity (buccal mucosa, dorsal tongue, ventral tongue and hard palate). The smears were graded for cell yield and dispersion on a three-point scale. The results were analyzed using the chi 2 test. The Cytobrush was found to be significantly more efficient than the wooden spatula, in terms of both cell yield (P less than .005) and cell dispersion (P less than .005). When each site was examined separately, the Cytobrush produced significantly better dispersion for the dorsal tongue, ventral tongue and buccal mucosa and a better cell yield for the tongue surfaces. No significant difference for cell yield or dispersion was found for the hard palate. The study showed that the Cytobrush is an effective instrument for use in exfoliative cytology of normal oral mucosa.