Eugenol is a phenylpropanoid formally derived from guaiacol with an allyl chain substituted para to the hydroxy group. It is a major component of clove essential oil, and exhibits antibacterial, analgesic and antioxidant properties. It has been widely used in dentistry to treat toothache and pulpitis. It has a role as an allergen, a human blood serum metabolite, a sensitiser, a volatile oil component, a flavouring agent, an EC 1.4.3.4 (monoamine oxidase) inhibitor, a radical scavenger, an antibacterial agent, an antineoplastic agent, an apoptosis inducer, an anaesthetic, an analgesic, a voltage-gated sodium channel blocker, a NF-kappaB inhibitor and an anti-inflammatory agent. It is a phenylpropanoid, a monomethoxybenzene, a member of phenols and an alkenylbenzene. It is functionally related to a guaiacol.