BACKGROUND: Reports of purported sensitization reactions to widely used prescription dermatologicals have raised questions concerning the clinical significance of these reports. The current study was designed to compare irritant and sensitization potentials of such marketed products and to evaluate the risks involved in their usage. METHODS: One hundred and eight healthy adult volunteers were evaluated for primary irritation and hypersensitivity following application under a double-blind paradigm of eight leading prescription dermatologic products and the vehicle cream of one product according to an intensified version of the Shelanski and Shelanski "Repeated Insult Patch Test." RESULTS: No clinically significant irritant or sensitization reactions were associated with applications of topical formulations containing clobetasol propionate, doxepin hydrochloride, metronidazole, mupirocin, oxiconazole nitrate, and terbinafine hydrochloride. The doxepin hydrochloride cream vehicle was also found to be nonirritating and nonsensitizing. Both calcipotriene and ketoconazole were moderate irritants and possible sensitization reactions were also associated with ketoconazole. CONCLUSION: Although every topically applied chemical has the potential to cause an adverse response in some individuals, the data obtained in this study for eight commercially available prescription dermatologic products indicate that most are quite safe and have very low risks of clinically significant irritation or sensitization.