Wormwood and Thujone
Thujone is a substance in wormwood (the common name of some species of artemisia plants) and some other plants, which is purported to have hallucinogenic or psychotropic effects. There are several types of wormwood, and these are used to flavor absinthe, bitters, vermouths, and bitter liqueurs.
Thujone is regulated in the United States and in other countries. In the United States, alcoholic beverages must be "thujone-free," which is defined as having a very small maximum amount of thujone (10 ppm). The FDA requires the level of thujone from wormwood and some other ingredients to be declared via laboratory testing.
Dried wormwood, absinthe kits, wormwood oil, and "absinthe essence" are available for sale online and in stores. Some advertise higher levels of thujone than what is legally allowed in the United States. Others do not specify the thujone content of the herbs or mixes. As described below, beverages containing wormwood in the USA must be legally thujone-free.
Absinthe historically was an alcoholic beverage flavored with grand wormwood (artemisia absinthium), and often anise, fennel, and/or licorice, plus other herbs. It is traditionally high in proof compared with other spirits, and is often green (absinthe verte) or clear (absinthe blanche) in color.
In the late 1800s and first years of the 1900s, absinthe was blamed for many types of societal problems in Europe. A sensational murder blamed on absinthe in Switzerland in 1905, and a campaign by the recovering wine industry after the phylloxera crisis, lead to absinthe bans in Europe and other parts of the world. [link] It is likely that many of the problems associated with absinthe were due not to the thujone in wormwood, but to absinthe's high alcohol strength, along with adulterants sometimes used by unscrupulous producers.
In the 1990s and 2000s, absinthe was re-legalized in many parts of the world, often with limits in place on the amount of thujone allowed to be present. [link]
A common misperception is that "real absinthe" was re-legalized in the United States in 2007, but the TTB merely clarified [link] its ruling on thujone content and allowed the word "absinthe" to appear on liquor labels in the USA again.
All absinthe and other alcoholic beverages must be "thujone-free" which the United States defines as "Based upon the level of detection of FDA's prescribed method for testing for the presence of thujone, TTB considers a product to be "thujone-free" if it contains less than 10 parts per million of thujone."
Other countries have different limits on thujone content.
Several types of wormwood/artemisia are used in spirits:
Artemisia absinthium = Grand Wormwood; used in absinthe
Artemisia pontica = Roman Wormwood; small absinthe; often used in vermouths
Artemisia vulgaris = Common Wormwood; mugwort; used in Herbsaint, vermouth, and other products
Artemisia genepi = Genepi, used in Genepy liqueurs along with other "lesser" wormwoods [link]
However other plants also contain thujone, including regulated ingredients (see below) yarrow, tansy, oak moss, and cedar, plus ingredients that are "generally recognized as safe" in the United States, including mint, oregano, and sage [link].
In the United States, "According to the FDA, alcoholic beverages must be thujone-free pursuant to 21 CFR 172.510." [link]
This applies not only to wormwood/grand wormwood/absinthe wormwood, but also to other ingredients [link]. According to 21 CFR 172.510:
|Common Name||Scientific Name||Limitations|
|Artemisia (wormwood)||Artemisia spp (spp = "several species")||Finished food thujone free 1|
|Cedar, white (aborvitae), leaves and twigs||Thuja occidentalis L||Finished food thujone free 1|
|Oak moss||Evernia prunastri (L.) Ach., E. furfuracea (L.) Mann, and other lichens||Finished food thujone free 1|
|Tansy||Tanacetum vulgare L||In alcoholic beverages only; finished alcoholic beverage thujone free1|
|Yarrow||Achillea millefolium L||In beverages only; finished beverage thujone free 1|
1 "As determined by using the method (or, in other than alcoholic beverages, a suitable adaptation thereof) in section 9.129 of the "Official Methods of Analysis of the Association of Official Analytical Chemists," 13th Ed. (1980)" [link]
Thus, if attempting to acquire label approval for an alcoholic beverage containing one of the above limited plants from the US TTB, the producer must have the product tested to show that it is within the legal limit.
- Thujone limits vary in different provinces.
- In Quebec, thujone in beverages is limited to 10 ppm (liqueur and herb-based beverages whose percentage of alcohol is ≥ 25% ABV) and 1 ppm (liqueur and herb-based beverages whose percentage of alcohol is < 25% ABV) according to this document [PDF link] hosted on the Société des alcools du Québec website.
- According to the Liquor Control Board of Ontario [link] α-Thujone in absinthe-based products have a maximum of 1 ppm. [Other tests measure alpha and beta thujone combined. According to this paper [link], "The content of β-thujone often exceeds that of α-thujone depending on the plant source, but the β-diastereomer is generally of lower toxicity."]
High levels of thujone, above what is legally allowed in beverages in the United States, can cause serious health problems. In one case, a person consumed about 1/3 ounces (10ml) of oil of wormwood purchased online, and it caused renal failure (kidney failure) and other serious problems [link].
As for lower levels of consumption of thujone-containing herbs, at least one study has concluded that the dangerous amount of thujone is much higher than what we would normally consume. In the article "Risk assessment of thujone in foods and medicines containing sage and wormwood--evidence for a need of regulatory changes?" [link, Regul Toxicol Pharmacol.], the authors concluded after a new study on rats that,
"we propose an ADI [acceptable daily intake] of 0.11 mg/kg bw[body weight]/day, which would not be reachable even for consumers of high-levels of thujone-containing foods (including absinthe). While fewer data are available concerning thujone exposure from medicines, we estimate that between 2 and 20 cups of wormwood or sage tea would be required to reach this ADI, and view that the short-term medicinal use of these herbs can also be regarded as safe."
"Theoretically, wormwood oil can cause an allergic reaction in people sensitive to the Asteraceae/Compositae family (12815). Members of this family include ragweed, chrysanthemums, marigolds, daisies, and many other herbs." [link]
Wormwood and other Thujone-Containing Materials at the Bar
In order to be in compliance with FDA guidelines in the United States, homemade products with any of the thujone-containing limited ingredients in the table above would need to contain under 10 ppm thujone. Some wormwood tinctures may list their thujone content, but any fresh or dried herbs likely would not. (And due to the nature of plants, there would be great variation between batches.)
It is not possible for us to give guidance on a 'safe' amount of any of these plants to use for home or the bar.
References and Resources:
"Acute Renal Failure Caused by Oil of Wormwood Purchased through the Internet" [link]