The potential of fragrances, physiological chemicals, natural products and a group of randomly selected chemicals to induce cancers by a genotoxic mechanism (i.e. "genotoxic" carcinogenesis) was compared using structure-activity relationships (SAR) models. Fragrances are significantly less likely to induce genotoxic carcinogenicity than randomly selected chemicals or natural products. With respect to the latter potential, fragrances were indistinguishable from normal mammalian physiological constituents.