Absinthe thujone is the chemical found in Absinthe’s vital ingredient, the plant known as Common Wormwood, or Artemisia Absinthium to give it its botanical name. The substance thujone was partly responsible for Absinthe being banned in the early 1900s in several countries across the world and thujone is still tightly regulated today https://absinthesupreme.com, especially in the United States (or states united).
Thujone was considered to be just like THC seen in cannabis and Absinthe was alleged to be psychoactive and have psychedelic effects causing hallucinations and insanity. Absinthe was popular with the Bohemian set in Montmartre in Paris and several artists and writers believed that Absinthe, the Green Fairy, gave them inspiration as well as their genius. Famous Absinthe drinkers include Oscar Wilde, Ernest Hemingway, Van Gogh, Gauguin, Degas, Baudelaire and Verlaine. Some say that Van Gogh’s madness was caused by Absinthe and that he cut off his ear under its effect 
. Absinthe was even blamed for a man murdering his family, although he had used many other strong alcoholic drinks following the Absinthe.
Prohibition campaigners used news of the murder to campaign for the suspending of Absinthe and blamed France’s growing problems of alcoholism on the emerald liquor.
Is Absinthe Thujone Hazardous?
Today’s studies suggest that it was actually the alcohol (ethanol) content of Absinthe which was dangerous instead of the thujone. Absinthe is twice as strong as spirits like whisky and vodka and can be 75% alcohol. Care should therefore be taken when ingesting Absinthe. Thujone is simply found in minute quantities and should therefore cause no major negative effects or health issues. The EU stipulates that alcohol based drinks with an ABV (alcohol by volume) level over 25% might only contain a maximum of 10mg/kg of thujone, beverages classed as “bitters” can contain approximately 35mg/kg, it is not completely clear which class Absinthe suits but many brands of Absinthe have much less than 35mg with a lot of being under 10mg/kg. In the US it is simply legal to get or sell Absinthes with trace quantities of thujone.
High doses of thujone may be dangerous causing convulsions but you would need to drink a substantial amount of Absinthe to consume that amount of thujone and it will be impossible to drink that amount, you would be comatosed from alcohol until then!
Absinthe Ingredients
It is said that Henri-Louis Pernod, who owned the first Absinthe distillery, used the herbs wormwood, aniseed, fennel, lemon balm, hyssop, angelica root, dittany, star anise, nutmeg, juniper and veronica to create his famous Pernod Absinthe. The essential oil from these herbs is mainly responsible for La Louche, the clouding which occurs when water is put into Absinthe. These herbs particularly the aniseed and anise are responsible for the distinctive aniseed or licorice taste of Absinthe and wormwood is mainly responsible for the bitter flavor. Absinthe is usually used as bitters in cocktails.
There are lots of brands of Absinthe or Absinthe substitutes that have been developed in the ban and so contain no Absinthe thujone or wormwood, but many would state that Absinthe just isn’t Absinthe without Absinthe thujone and the bitter taste of wormwood. If you’d like real Absinthe look for brands that contains wormwood or Absinthe thujone.