Perfumes are carefully formulated mixtures of natural or synthetic oils, diluted with a suitable solvent. The dilution is important, because the fragrance oils contain sufficiently high concentrates of volatile components to cause allergic reactions or even injury. So perfumes are frequently diluted in ethanol or an ethanol and water mixture, although the oils can also be mixed with jojoba, coconut oil, or even wax, so that most perfumes contain only 20% to 40% of aromatic compounds. Other fragrance products—eau de parfum, eau de toilette, eau de cologne—are formulated so that they have even lower concentrations of perfume oils. Eau de parfum contains, perhaps, 10% to 30% of undiluted oils; eau de toilette, between five and 20%; and eau de cologne even less, between two and three per cent of perfume oils