Wormwood (also known as Mugwort) is a family of herbaceous perennials & annuals of the Artemisia genus. They are primarily grown for their absinthin and thujone content.

The most well-known cultivars are A. absinthium (Common Wormwood, used for the commercial production of absinthe) and A. herba-alba (White Wormwood, or Biblical Wormwood).

Wormwood has been prized by medical practitioners & folk witches for millenia. Anecdotal evidence suggests these plants have anti-inflammatory, antifungal, neuroprotective, insecticidal, antimicrobial, antidepressant and hallucinogenic properties. Wormwood has also historically been used to treat malaria & parasitic infestations, and more recently conditions such as diabetes and Crohn's disease.

Modern science has isolated much of wormwood's medicinal qualities to several chemical compounds:

Absinthin (also spelled absinthiin or absynthine) is a triterpene lactone that occurs primarily in A. absinthium, and to a far lesser extent in A. pontica. It is absent entirely from other Artemisia cultivars.

Absinthin is extremely bitter, and it is why wormwood is used as a culinary bittering agent, most notably in the alcoholic drinks Absinthe and Vermouth. It exhibits strong anti-inflammatory properties, and seems to potentiate the medicinal properties of the other compounds in wormwood as well.

Artemisinin is a sesquiterpene lactone that only occurs in A. annua (or Sweet Wormwood). It is primarily used for the treatment of malaria, and holds antiparasitic, antiviral, anti-inflammatory & immunomodulatory properties as well. For centuries, the Chinese have brewed A. annua as a tea for its medical properties.

Scopoletin and Scoparone are a pair of compounds with noted anti-inflammatory, antioxidant, antimicrobial, antifungal and other medicinal properties. They are also mild sedatives and antidepressants (MAO-A inhibition). They occur in highest concentrations in A. abrotanum, A. scoparia, A. capillaris and A. umbelliformis.

Thujone is a monoterpene compound that occurs primarily as one of two stereoisomers: α-thujone and β-thujone. It is a GABA_A receptor antagonist, and is known to act on the 5-HT3 and α7 nicotinic receptors as well. While it occurs throughout most of the Artemisia genus (and even in other plants such as common sage), it occurs in especially high concentrations in A. herba-alba and A. absinthium. It can be found in lighter concentrations in A. vulgaris and A. pontica, and not-insignificant amounts can be found in A. argyi and A. princeps as well.

It has long-thought to be the primary compound responsible for Wormwood's mild hallucinogenic properties. Like many psychoactive compounds, thujone has not seen much study in 21st century western medicine. Given thujone's ability to potentiate other drugs, it is likely acting in concert with various other compounds that occur within Wormwood cultivars.

Other than its use as an entheogen, thujone has no medicinal value. Most “medicinal” wormwood plants are cultivars with no thujone, such as A. annua or A. abrotanum. Other cultivars prized by traditional Asian medicine (such A. argyi & A. princeps) also have comparatively low amounts of thujone. This is because thujone is toxic in large amounts, where it acts as a lethal convulsant. While it's LD50 in humans is unknown, it hovers around 45 mg/kg in mice. A quick survey of wormwood & thujone overdoses returns tales of people consuming mammoth amounts of absinthe or concentrated essential oil from the wormwood plant. It can be safely smoked or consumed in moderation.