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 a sensitiser, a volatile oil component, an antibacterial agent, an analgesic, an antineoplastic agent, a flavouring agent, an EC 1.4.3.4 (monoamine oxidase) inhibitor, a voltage-gated sodium channel blocker, an anaesthetic, a radical scavenger, an allergen, an anti-inflammatory agent, an apoptosis inducer, a NF-kappaB inhibitor and a human blood serum metabolite. It is an alkenylbenzene, a monomethoxybenzene, a phenylpropanoid and a member of phenols. It is functionally related to a guaiacol.