Lemon essential oil, also known as Citrus limon oil, is extracted from lemon peels, which have many volatile oil glands in their pits. Approximately 1,000 lemons are needed to produce one pound of lemon oil. The citrus scent of lemons comes from a chemical compound called limonene, which comprises the majority of lemon oil.
Lemons were used by ancient Indians, Egyptians, and Romans as a remedy for infectious diseases. Today, they are commonly grown in Europe and the United States, and are used in various products.