Lemon essential oil (Citrus limon) is cold-pressed from the peel and is composed primarily of d-limonene (up to 70%), beta-pinene, and gamma-terpinene, with trace amounts of citral (neral + geranial) contributing the characteristic lemon aroma. D-limonene shows antioxidant and chemopreventive properties in preclinical studies.^[1] Peel-pressed lemon oil contains furanocoumarins (bergapten) and is phototoxic; expressed oil must be distinguished from steam-distilled (furanocoumarin-free) versions.^[2]