Linalool

Linalool is a fragrance compound that occurs naturally in over 200 plants, including lavender and coriander, and is also made synthetically for use in perfumes, lotions, shampoos, and household cleaners. It gives products a light, floral smell. On its own it's not particularly toxic, but once a bottle is opened and linalool is exposed to oxygen and light over time, it can slowly convert into linalool hydroperoxides — breakdown products that are much more likely to cause allergic contact dermatitis (itchy, red, inflamed skin) in people who are sensitised to fragrance chemicals. Most people can use products containing it without any problem; the main concern is for people with fragrance allergies or very sensitive skin.