Geraniol, also known as beta-Geraniol, (E)-nerol (the isomer of nerol) or geranyl alcohol, is a monoterpenoid alcohol. It belongs to the class of organic compounds known as acyclic monoterpenoids. These are monoterpenes that do not contain a cycle. Monoterpenoids are terpenes that contain 10 carbon atoms and are comprised of two isoprene units. In plants, the biosynthesis of monoterpenes is known to occur mainly through the methyl-erythritol-phosphate (MEP) pathway in the plastids (PMID:7640522 ). Geranyl diphosphate (GPP) is a key intermediate in the biosynthesis of cyclic monoterpenes. GPP undergoes several cyclization reactions to yield a diverse number of cyclic arrangements. beta-Geraniol is an isoprenoid lipid molecule that is very hydrophobic, practically insoluble in water, and relatively neutral. beta-Geraniol has a sweet, citrus, and floral taste. beta-Geraniol is found in highest concentrations in common grapes, black walnuts, and common thymes and in lower concentrations in cardamoms, common oregano, and gingers. beta-Geraniol has also been detected in lemon verbena, oval-leaf huckleberries, common pea, sweet cherries, and nopals. It is found as an alcohol and as its ester in many essential oils including geranium oil. It is the primary part of rose oil, palmarosa oil, and citronella oil (Java type) and occurs in small quantities in geranium, lemon, and many other essential oils. Because it has a rose-like odor, it is commonly used in perfumes. It is used to create flavors such as peach, raspberry, grapefruit, red apple, plum, lime, orange, lemon, watermelon, pineapple, and blueberry. An alternate application has been found in the use of insect repellents or deterrants. Though it may repel mosquitoes, flies, lice, cockroaches, ants, and ticks, it is also produced by the scent glands of honey bees to help them mark nectar-bearing flowers and locate the entrances to their hives (http//doi:10.1051/apido:19900403). Extensive testing by Dr. Jerry Butler at the University of Florida has shown geraniol to be one of nature's most effective insect repellents (PMID:20836800).