thujone

Thujone is a monoterpene ketone found in the essential oils of several Artemisia species, most notably Artemisia absinthium (wormwood). It occurs in two stereoisomeric forms, alpha-thujone and beta-thujone, and is present in smaller amounts in other plants such as sage (Salvia officinalis), tansy, and dill.

Historically, thujone was associated with absinthe, a green spirit once believed to provoke hallucinations. Modern absinthe, when produced under regulatory control, contains thujone in very limited amounts, and widely reported hallucinogenic effects at typical consumption levels are not supported by evidence.

Pharmacology and toxicity: Thujone is known to act as a GABA_A receptor antagonist. At high doses it can be neurotoxic and convulsant in animal studies, though human data are limited and effects depend on dose and context. It is not considered a stimulant, and typical exposures from foods or beverages are much lower than levels associated with toxicity in research settings.

Safety and regulation: Because of its potential neurotoxicity, thujone content is regulated in many countries, particularly for alcoholic beverages. Historical restrictions on absinthe prompted modern regulatory limits, and products containing thujone are often subject to labeling or compositional restrictions in several jurisdictions.

Uses and occurrence: In addition to its presence in wormwood, thujone occurs in trace amounts in various essential oils used for flavoring and fragrance. It is mainly encountered as a minor constituent rather than a primary ingredient in most foods and beverages.