Menthol, a cyclic terpene alcohol found in high concentrations in oils of peppermint and cornmint, has been widely used in over-the-counter medications, cosmetics and confectionery for over a century. However, its clinical pharmacology remains incompletely understood and its sensitization potential and irritant properties have not been thoroughly studied. Analysis of the menthol structure in a quantitative structure-activity relationship model does not identify any protein-reactive functions. Considering the extensive use of menthol there have been only few reports of adverse dermatological effects. After performing an extensive review of the reported cases of sensitization to menthol, we concluded that the literature does not adequately document the clinical relevance of the patch test reactions nor the impact of irritant reactions. We propose a comprehensive approach when testing with a nonstandard substance such as menthol.