Evaluation of Giemsa-stained smears of scrapings from the base of vesicles or ulcers ( Tzanck preparation) for the presence of multinucleated giant cells and/or intracellular inclusions were diagnostic for herpesvirus in 18 of 21 cases (86%) of culturally proved herpesvirus infections. Smears from four patients with varicella-zoster infection also revealed cytologic alterations characteristic of herpesvirus.