Terpineol, an unsaturated monocyclic alcohol of the terpene class. Terpineol occurs as colorless crystals and has a lilac odor. Its melting point is 36.9°C, and its boiling point 219°C. It is soluble in alcohol but not in water. Terpineol is contained in insignificant amounts in many essential oils, such as orange oil and neroli oil.

Terpineol is obtained industrially by dehydration of terpin hydrate or by direct hydration of the terpene hydrocarbons contained in turpentine oil. When obtained synthetically, it also contains the isomers β-and-γ-terpineol. Terpineol is used as an ingredient in perfumes and as a foaming agent in the flotation of ores of nonferrous metals. The esters of terpineol, such as terpinyl acetate, are also used in perfumes.

Citronellal is a monoterpenoid, the main component in the mixture of terpenoid chemical compounds that give citronella oil its distinctive lemon scent. Citronellal is a major isolate in distilled oils from the plants Cymbopogon, lemon-scented gum, and lemon-scented teatree. The (–)-(S)-enantiomer of citronellal makes up up to 80% of the leaf oil from kaffir lime leaves and is the compound responsible for its characteristic aroma. Citronellal has insect repellent properties, and research shows high repellent effectiveness against mosquitoes. Research shows that citronellal has strong antifungal qualities.

Geraniol is a monoterpenoid and an alcohol. It is the primary part of rose oil, palmarosa oil, and citronella oil (Java type). It also occurs in small quantities in geranium, lemon, and many other essential oils. It appears as a clear to pale-yellow oil that is insoluble in water, but soluble in most common organic solvents. It has a rose-like scent and is commonly used in perfumes. It is used in flavors such as peach, raspberry, grapefruit, red apple, plum, lime, orange, lemon, watermelon, pineapple, and blueberry.

Research has shown geraniol to be an effective plant-based mosquito repellent. On the other hand, it can attract bees as it is produced by the scent glands of honey bees to help them mark nectar-bearing flowers and locate the entrances to their hives.

Although geraniol and other flavor compounds are found naturally in well-aged tobacco, geraniol is listed in a 1994 report from cigarette companies as one of the 599 additives to cigarettes to improve their flavor.

Isopulegol is a colorless, clear liquid with an odor of mint. There are four diastereomers of named isopulegol, iso-isopulegol, neo-isopulegol and neo-iso-isopulegol.

Isopulegol can be used as flavoring agent, flavoring substance, or for the cooling effect, as well as menthol. It is also used to prepare other synthetic flavoring substances; especially optically active menthol stereoisomers via catalytic hydrogenation of the double carbon-carbon bond in isopulegol. Also menthofuraan (which occurs in peppermint flowers), and the sweetener hernandulcin (which is present in the plant Lippia dulcis) may be prepared from isopulegol.

Linalool is a naturally occurring terpene alcohol chemical found in many flowers and spice plants with many commercial applications, the majority of which are based on its pleasant scent (floral, with a touch of spiciness). Over 200 species of plants produce linalool, mainly from the families Lamiaceae (mints, scented herbs), Lauraceae (laurels, cinnamon, rosewood), and Rutaceae (citrus fruits), but also birch trees and other plants, from tropical to boreal climate zones. It has also been found in some fungi and cannabis.

Linalool is used as a scent in 60–80% of perfumed hygiene products and cleaning agents including soaps, detergents, shampoos, and lotions. It is also used as a chemical intermediate. One common downstream product of linalool is vitamin E. In addition, linalool is used by pest professionals as a flea, fruit fly and cockroach insecticide. Linalool is used in some mosquito-repellent products; however, the EPA notes that "a preliminary screen of labels for products containing [l]inalool (as the sole active ingredient) indicates that efficacy data on file with the Agency may not support certain claims to repel mosquitos."

Menthone is a naturally occurring organic compound, is the most abundant in nature of the four possible stereoisomers. Menthone is a monoterpene and a ketone. It is structurally related to menthol which has a secondary alcohol in place of the carbonyl. Menthone is used in perfumery and cosmetics for its characteristic aromatic and minty odor.

Menthone is a constituent of the essential oils of pennyroyal, peppermint, Mentha arvensis, Pelargonium geraniums, and others. In most essential oils, it is a minor compound. Menthone is a naturally occurring pesticide used in some products such as Ecosmart Roach Killer.

Nerol is a monoterpene found in many essential oils such as lemongrass and hops. It was originally isolated from neroli oil, hence its name. This colourless liquid is used in perfumery. Like geraniol, nerol has a sweet rose odor but it is considered to be fresher.

Isomeric with nerol is geraniol, wherein the double bond is trans. Nerol readily loses water to form dipentene. Nerol can be synthesized by pyrolysis of β-Pinene, which affords myrcene. Hydrochlorination of myrcene gives a series of isomeric chlorides, one of which converts to neryl acetate.