Thujone is a ketone and a monoterpene that occurs naturally in two diastereomeric (epimeric) forms: (−)-α-thujone and (+)-β-thujone. It has a menthol odor. Though it is best known as a chemical compound in the spirit absinthe, which contains only small quantities of thujone, it is unlikely to be responsible for absinthe's alleged psychedelic effects. Thujone acts on GABA as an antagonist and as a component of several essential oils, is also used in perfumery. As a competitive antagonist of GABA, Thujone alone is considered to be convulsant, though by interfering with the inhibitory transmitter GABA, it may convey stimulating, mood elevating effects at low doses.