, parasite cleansing, RBC Herbal, Inc

Anthelmintic; Antiseptic; Antispasmodic; Carminative; Cholagogue; Emmenagogue; Febrifuge; Homeopathy; Hypnotic; Stimulant; Stomachic; Tonic; Vermifuge.

Historical or traditional use (may or may not be supported by scientific studies): Wormwood is perhaps best known because of the use of its oil to prepare certain alcoholic beverages, most notably vermouth and absinthe.

As a traditional medicine, wormwood was used by herbalists as a bitter to improve digestion, to fight worm infestations, and to stimulate menstruation.² It was also regarded as a useful remedy for liver and gallbladder problems.

Active constituents: Wormwood oil contains the toxins thujone and isothujone. Very little of this oil is present in ordinary wormwood teas or tinctures.³ Also existent in the plant are strong bitter agents known as absinthin and anabsinthin. These stimulate digestive and gallbladder function.⁴ Modern herbal medicine rarely uses wormwood alone. It is typically combined with herbs such as peppermint or caraway to treat heartburn and even irritable bowel syndrome. Clinical trials are lacking to support the use of wormwood for any indication, however.

How much is usually taken? A wormwood tea can be made by adding 1/2 to 1 teaspoon (2.5 to 5 grams) of the herb to 1 cup (250 ml) of boiling water, then steeping for ten to fifteen minutes.⁵ Many doctors recommend drinking three cups (750 ml) each day. Tincture, 10�20 drops in water, can be taken ten to fifteen minutes before each meal.⁶ Either preparation should not be used consecutively for more than four weeks.⁷

Are there any side effects or interactions? Longer-term use (over four weeks) or intake of amounts higher than those recommended can cause nausea, vomiting, insomnia, restlessness, vertigo, tremors, and seizures.⁸

Short-term use (two to four weeks) of a wormwood tea or tincture has not resulted in any reports of significant side effects.

One study found there were no side effects when using less than 1 ml tincture three times per day for as long as nine months to promote digestive function.¹⁰ Nevertheless, consult with a healthcare professional knowledgeable in herbal medicine before taking wormwood. Wormwood is not recommended during pregnancy and breast-feeding.¹¹

At the time of writing, there were no well-known drug interactions with wormwood.

Wormwood is a very bitter plant with a long history of use as a medicinal herb. It is valued especially for its tonic effect on the liver, gallbladder and digestive system, and for its vermicidal activity[4, 238, 254]. It is an extremely useful medicine for those with weak and underactive digestion. It increases stomach acid and bile production, improving digestion and the absorption of nutrients[254]. It also eases wind and bloating and, if taken regularly, helps the body return to full vitality after a prolonged illness[254].

The leaves and flowering shoots are anthelmintic, antiinflammatory, antiseptic, antispasmodic, antitumor, carminative, cholagogue, emmenagogue, febrifuge, hypnotic, stimulant, stomachic, tonic and vermifuge[4, 9, 21, 46, 165, 222, 254]. The plant is harvested as it is coming into flower and then dried for later use[4]. Use with caution[21], the plant should be taken internally in small doses for short-term treatment only, preferably under the supervision of a qualified practitioner[238].
The extremely bitter leaves are chewed to stimulate the appetite[222]. The bitter taste on the tongue sets off a reflex action, stimulating stomach and other digestive secretions[254]. The leaves have been used with some success in the treatment of anorexia nervosa[244].

The plant is applied externally to bruises and bites[238]. A warm compress has been used to ease sprains and strained muscles[257].

A homeopathic remedy is made from the leaves[9]. It is used to stimulate bile and gastric juice production and to treat disorders of the liver and gall bladder[9].

As its name implies, wormwood has been used to expel worms from people and animals. Whatever antiparasitic properties wormwood has may be partially due to its

-santonin content (Perez-Souto et al 1992), which is recognized as a medicine for parasitic diseases.

Wormwood contains unidentified antimalarial substance(s). Alcoholic extracts of the dried leaves have 'considerable antimalarial potential' when administered orally, subcutaneously, or intraperitoneally to mice (Zafar, Hamdard, & Hameed 1990).

Wormwood leaves are used traditionally in Pakistan as an antipyretic (anti-fever) and an active antipyretic compound has been isolated from the dried leaves. This compound alleviates yeast-induced pyrexia in rabbits (Ikramet al 1987).

Dilute (1:1000) oil of wormwood has some antimicrobial activity. Kaul, Nigam and Dhar (1976) found that the dilute oil inhibited the growth of 4 (out of 7) different types of bacteria.

Wormwood is also hepatoprotective (liver protecting). Gilani and Janbaz (1995) found that an aqueous-methanolic extract of Artemisia absinthium protected against acetaminophen and CCl4-induced hepatotoxicity in mice. This protection seems to be at least partially due to inhibition of microsomal drug metabolizing enzymes (MDME), since the plant extract prolonged the sleep-inducing effects of pentobarbital in mice. Gilani and Janbaz speculate that this putative MDME inhibition may be due to sesartemin, which has the methylene-dioxybenzene group common to MDME inhibitors. The presence of antioxidants and calcium-channel blockers in wormwood (Gilani 1994) also probably contribute to its hepatoprotective effects.

Known Hazards: The plant is poisonous if used in large quantities. The plant contains thujone. In small quantities this acts as a brain stimulant but is toxic in excess.

Perennial growing to 1m by 0.6m . It is hardy to zone 4 and is not frost tender. It is in flower from July to August. The scented flowers are hermaphrodite (have both male and female organs) and are pollinated by Wind. We rate it 3 out of 5 for usefulness.

The plant prefers light (sandy) and medium (loamy) soils, requires well-drained soil and can grow in nutritionally poor soil. The plant prefers acid, neutral and basic (alkaline) soils and can grow in very alkaline soil. It can grow in semi-shade (light woodland) or no shade. It requires dry or moist soil and can tollerate drought.

Leaves are occasionally used as a flavouring[27, 177, 183]. Caution is advised, prolonged use is known to have a detrimental effect - see the notes above on toxicity[K].

The fresh or dried shoots are said to repel insects and mice[6, 18, 20, 169], they have been laid amongst clothing to repel moths and have also been used as a strewing herb[4, 14, 257]. An infusion of the plant is said to discourage slugs and insects[14, 18, 201]. The plant contains substances called sesquiterpene lactones, these are strongly insecticidal[254].

Succeeds in any soil but it is best in a poor dry one with a warm aspect[37]. Established plants are very drought tolerant[190, 200]. Plants are longer lived, more hardy and more aromatic when they are grown in a poor dry soil[245]. Easily grown in a well-drained circumneutral or slightly alkaline loamy soil, preferring a sunny position[1, 200]. Prefers a shady situation according to another report[4]. Tolerates a pH in the range 4.8 to 8.2.

Wormwood is occasionally grown in the herb garden, there are some named forms[187]. The growing plant is said to inhibit the growth of fennel, sage, caraway, anise and most young plants, especially in wet years[14, 18, 20]. Wormwood is a good companion for carrots, however, helping to protect them from root fly[201].

This herb was at one time the principal flavouring in the liquer 'Absinthe' but its use has now been banned in most countries since it was too efective against diseases, and since prolonged consumption can lead to chronic poisoning, epileptiform convulsions and degeneration of the central nervous system[244].

The scent of the plant attracts dogs[169].

Members of this genus are rarely if ever troubled by browsing deer[233].

Seed - surface sow from late winter to early summer in a greenhouse. The seed usually germinates within 2 - 26 weeks at 15�c[134]. When they are large enough to handle, prick the seedlings out into individual pots. They can be planted out in the summer, or kept in pots in a cold frame for the winter and then planted out in the spring.

Cuttings of half-ripe wood, July/August in a frame.

Division in spring or autumn.

See the PFAF Links Pages for other sources or the The Gatherer where you can search many other sources all in one go.

[K] Ken Fern
Notes from observations, tasting etc at Plants For A Future and on field trips.

[1] F. Chittendon. RHS Dictionary of Plants plus Supplement. 1956 Oxford University Press 1951
Comprehensive listing of species and how to grow them. Somewhat outdated, it has been replaces in 1992 by a new dictionary (see [200]).

[4] Grieve. A Modern Herbal. Penguin 1984 ISBN 0-14-046-440-9
Not so modern (1930's?) but lots of information, mainly temperate plants.

[6] Mabey. R. Plants with a Purpose. Fontana 1979 ISBN 0-00-635555-2
Details on some of the useful wild plants of Britain. Poor on pictures but otherwise very good.

[9] Launert. E. Edible and Medicinal Plants. Hamlyn 1981 ISBN 0-600-37216-2
Covers plants in Europe. a drawing of each plant, quite a bit of interesting information.

[14] Holtom. J. and Hylton. W. Complete Guide to Herbs. Rodale Press 1979 ISBN 0-87857-262-7
A good herbal.

[17] Clapham, Tootin and Warburg. Flora of the British Isles. Cambridge University Press 1962
A very comprehensive flora, the standard reference book but it has no pictures.

[18] Philbrick H. and Gregg R. B. Companion Plants. Watkins 1979
Details of beneficial and antagonistic relationships between neighbouring plants.

[20] Riotte. L. Companion Planting for Successful Gardening. Garden Way, Vermont, USA. 1978 ISBN 0-88266-064-0
Fairly good.

[21] Lust. J. The Herb Book. Bantam books 1983 ISBN 0-553-23827-2
Lots of information tightly crammed into a fairly small book.

[27] Vilmorin. A. The Vegetable Garden. Ten Speed Press ISBN 0-89815-041-8
A reprint of a nineteenth century classic, giving details of vegetable varieties. Not really that informative though.

[37] Thompson. B. The Gardener's Assistant. Blackie and Son. 1878
Excellent general but extensive guide to gardening practices in the 19th century. A very good section on fruits and vegetables with many little known species.

[46] Uphof. J. C. Th. Dictionary of Economic Plants. Weinheim 1959
An excellent and very comprehensive guide but it only gives very short descriptions of the uses without any details of how to utilize the plants. Not for the casual reader.

[61] Usher. G. A Dictionary of Plants Used by Man. Constable 1974 ISBN 0094579202
Forget the sexist title, this is one of the best books on the subject. Lists a very extensive range of useful plants from around the world with very brief details of the uses. Not for the casual reader.

[100] Polunin. O. Flowers of Europe - A Field Guide. Oxford University Press 1969 ISBN 0192176218
An excellent and well illustrated pocket guide for those with very large pockets. Also gives some details on plant uses.

[134] Rice. G. (Editor) Growing from Seed. Volume 2. Thompson and Morgan. 1988
Very readable magazine with lots of information on propagation. An interesting article on Ensete ventricosum.

[165] Mills. S. Y. The Dictionary of Modern Herbalism.
An excellent small herbal.

[169] Buchanan. R. A Weavers Garden.
Covers all aspects of growing your own clothes, from fibre plants to dyes.

[177] Kunkel. G. Plants for Human Consumption. Koeltz Scientific Books 1984 ISBN 3874292169
An excellent book for the dedicated. A comprehensive listing of latin names with a brief list of edible parts.

[183] Facciola. S. Cornucopia - A Source Book of Edible Plants. Kampong Publications 1990 ISBN 0-9628087-0-9
Excellent. Contains a very wide range of conventional and unconventional food plants (including tropical) and where they can be obtained (mainly N. American nurseries but also research institutes and a lot of other nurseries from around the world.

[187] Phillips. R. & Rix. M. Perennials Volumes 1 and 2. Pan Books 1991 ISBN 0-330-30936-9
Photographs of over 3,000 species and cultivars of ornamental plants together with brief cultivation notes, details of habitat etc.

[190] Chatto. B. The Dry Garden. Dent 1982 ISBN 0460045512
A good list of drought resistant plants with details on how to grow them.

[200] Huxley. A. The New RHS Dictionary of Gardening. 1992. MacMillan Press 1992 ISBN 0-333-47494-5
Excellent and very comprehensive, though it contains a number of silly mistakes. Readable yet also very detailed.

[201] Allardice.P. A - Z of Companion Planting. Cassell Publishers Ltd. 1993 ISBN 0-304-34324-2
A well produced and very readable book.

[222] Foster. S. & Duke. J. A. A Field Guide to Medicinal Plants. Eastern and Central N. America. Houghton Mifflin Co. 1990 ISBN 0395467225
A concise book dealing with almost 500 species. A line drawing of each plant is included plus colour photographs of about 100 species. Very good as a field guide, it only gives brief details about the plants medicinal properties.

[233] Thomas. G. S. Perennial Garden Plants J. M. Dent & Sons, London. 1990 ISBN 0 460 86048 8
A concise guide to a wide range of perennials. Lots of cultivation guides, very little on plant uses.

[238] Bown. D. Encyclopaedia of Herbs and their Uses. Dorling Kindersley, London. 1995 ISBN 0-7513-020-31
A very well presented and informative book on herbs from around the globe. Plenty in it for both the casual reader and the serious student. Just one main quibble is the silly way of having two separate entries for each plant.

[244] Phillips. R. & Foy. N. Herbs Pan Books Ltd. London. 1990 ISBN 0-330-30725-8
Deals with all types of herbs including medicinal, culinary, scented and dye plants. Excellent photographs with quite good information on each plant.

[245] Genders. R. Scented Flora of the World. Robert Hale. London. 1994 ISBN 0-7090-5440-8
An excellent, comprehensive book on scented plants giving a few other plant uses and brief cultivation details. There are no illustrations.

[254] Chevallier. A. The Encyclopedia of Medicinal Plants Dorling Kindersley. London 1996 ISBN 9-780751-303148
An excellent guide to over 500 of the more well known medicinal herbs from around the world.

[257] Moerman. D. Native American Ethnobotany Timber Press. Oregon. 1998 ISBN 0-88192-453-9
Very comprehensive but terse guide to the native uses of plants. Excellent bibliography, fully referenced to each plant, giving a pathway to further information. Not for the casual reader.

Wormwood - Artemisia absinthium

Other Common Names: Absinth Sagewort, Absinth Wormwood, Absinthe, Ajenjo, Ajenjo Oficial, Common Wormwood, Feuilles Ameres, Niga-Yomogi, Old Woman, Oldman, Pelin, Wormswood, Artemisia absinthum

Range: Britain, Europe, North Africa, and western Asia. Now also in N. Amercia.

Habitat: Waste land, rocks and screes. Plants are longer lived, more hardy and more aromatic when they are grown in a poor dry soil.

The genus is named Artemisia from Artemis, the Greek name for Diana. In an early translation of the Herbarium of Apuleius we find:

"Of these worts that we name Artemisia, it is said that Diana did find them and delivered their powers and leechdom to Chiron the Centaur, who first from these Worts set forth a leechdom, and he named these worts from the name of Diana, Artemis, that is Artemisias."

The Common Wormwood held a high reputation in medicine among the Ancients. According to the Ancients, Wormwood counteracted the effects of poisoning by hemlock, toadstools and the biting of the seadragon. The plant was of some importance among the Mexicans, who celebrated their great festival of the Goddess of Salt by a ceremonial dance of women, who wore on their heads garlands of Wormwood.

With the exception of Rue, Wormwood is the bitterest herb known, but it is very wholesome and used to be in much request by brewers for use instead of hops. The leaves resist putrefaction, and have been on that account a principal ingredient in antiseptic fomentations.

The intensely bitter, tonic and stimulant qualities have caused Wormwood not only to be an ingredient in medicinal preparations, but also to be used in various liqueurs, of which absinthe is the chief, the basis of absinthe being absinthol, extracted from Wormwood. Wormwood, as employed in making this liqueur, bears also the name 'Wermuth' - preserver of the mind - from its medicinal virtues as a nervine and mental restorative. If not taken habitually, it soothes spinal irritability and gives tone to persons of a highly nervous temperament. Suitable allowances of the diluted liqueur will promote salutary perspiration and may be given as a vermifuge. Inferior absinthe is generally adulterated with copper, which produces the characteristic green color.

The drug, absinthium, is rarely employed, but it might be of value in nervous diseases such as neurasthenia, as it stimulates the cerebral hemispheres, and is a direct stimulant of the cortex cerebri. When taken to excess it produces giddiness and attacks of epileptiform convulsions. Absinthium occurs in the British Pharmacopoeia in the form of extract, infusion and tincture, and is directed to be extracted also from A. maritima, the Sea Wormwood, which possesses the same virtues in a less degree, and is often more used as a stomachic than the Common Wormwood. Commercially this often goes under the name of Roman Wormwood, though that name really belongs to A. Pontica.

The leaves and flowering shoots are anthelmintic, anti-inflammatory, antiseptic, antispasmodic, antitumor, carminative, cholagogue, emmenagogue, febrifuge, hypnotic, stimulant, stomachic, tonic and vermifuge. The plant is harvested as it is coming into flower and then dried for later use. Use with caution, the plant should be taken internally in small doses for short-term treatment only, preferably under the supervision of a qualified practitioner. It should not be prescribed for children or pregnant women. See also the notes on toxicity.

The extremely bitter leaves are chewed to stimulate the appetite. The bitter taste on the tongue sets off a reflex action, stimulating stomach and other digestive secretions. The leaves have been used with some success in the treatment of anorexia nervosa.

The plant is applied externally to bruises and bites. A warm compress has been used to ease sprains and strained muscles.

A homeopathic remedy is made from the leaves. It is used to stimulate bile and gastric juice production and to treat disorders of the liver and gall bladder.

The fresh or dried shoots are said to repel insects and mice, they have been laid amongst clothing to repel moths and have also been used as a strewing herb. An infusion of the plant is said to discourage slugs and insects. The plant contains substances called sesquiterpene lactones, these are strongly insecticidal.

Known Hazards: The plant is poisonous if used in large quantities. Even small quantities have been known to cause nervous disorders, convulsions, insomnia etc. Just the scent of the plant has been known to cause headaches and nervousness in some people. The plant contains thujone. In small quantities this acts as a brain stimulant but is toxic in excess. Absinthe, popular in the nineteenth century in Europe, caused several cases of brain damage and even death and was banned in most places in the early twentieth century.

Sources:

- Plants For A Future - A Resource and Information Centre for Edible and other useful plants.
- Chevallier. A. The Encyclopedia of Medicinal Plants Dorling Kindersley. London 1996 ISBN 9-780751-303148

Information on wormwood's traditional uses and names can be found by consulting the entry for wormwood in the AGIS Ethnobotany Database.
A nice description of wormwood's appearance, biology, and habitats can be found in the Nature Conservancy's Element Stewardship Abstract on wormwood. Although the abstract is aimed at providing information on managing land and plants, it is still worth checking out.

Duke, in the CRC Handbook of Medicinal Herbs gives the constituents of wormwood as:

Wormwood oil is produced by steam distillation of the leaves and flowering tops of dried wormwood. In terms of smell, appearance, and flavor, Arctander (1960) describes wormwood oil as:

It is possible to buy wormwood oil from companies that sell essential oils. Caution should be exercised with these oils since they can contain significant amounts of pharmacologically active and/or toxic compounds. Some of these compounds may be absorbed through the skin. If enough essential oil is absorbed or ingested, life-threatening medical problems, including convulsions, kidney failure, and muscle disintegration (rhabdomyolysis), may result.

Wormwood has been used medicinally since antiquity. Many of its uses have been supported by modern research. However, for each situation in which wormwood might be useful, there are probably safer herbal and non-herbal alternatives. Wormwood is rarely recommended these days. In fact, the prominent herbalist, Michael Moore, in his list of Herbal-Medical Contraindications categorizes Artemisia absinthium "as lacking any socially redeeming value." As you read on, you may wish to keep this in mind. What follows is neither a source of medical advice nor a guide to self-medication.

As its name implies, wormwood has been used to expel worms from people and animals. However, Caius and Mhasker (1920) did not find oil of wormwood to be an effective antihelmintic when tested against the hookworm. Whatever antiparasitic properties wormwood has may be partially due to its

-santonin content (Perez-Souto et al 1992), which is recognized as a medicine for parasitic diseases. Of course, wormwood's measurable toxicity prevents modern herbalists from recommending it.

Dilute (1:1000) oil of wormwood has some antimicrobial activity. Kaul, Nigam and Dhar (1976) found that the dilute oil inhibited the growth of 4 (out of 7) different types of bacteria.

Table II (below) lists the thujone content of many different plants' oils including the Artemisia genus. This list is not exhaustive and I would welcome (referenced) additions. Because the thujone content of plant specimens varies depending on a large number of factors, this table should only be used to give a rough idea of a plant's thujone content. For example, oil from the common culinary herb, sage (Salvia officinalis), is said to contain from 15% - 60% thujone (assayed as 42.5% in the table below). Since sage is GRAS (Generally Recognized As Safe) and widely consumed, its thujone content could be seen as evidence of thujone's relative safety or as evidence of dangerously lax regulation.

monoterpene, thujone, is considered a psychoactive convulsant. The sources of thujone in absinthe are the herbs wormwood (Artemisia absinthium) and Roman wormwood (Artemisia pontica). There is good evidence that both thujone and wormwood have psychoactive properties. Some have suggested that this effect is due to thujone binding at the cannabinoid receptor, at which the active components in marijuana act (delCastillo et al 1974). This seems unlikely. Furthermore, it is not even clear that thujone is present in sufficient quantities to play a role in absinthe intoxication. However, it is possible that thujone accumulates in the body and plays a role in the psychoactivity and toxicity of chronic absinthe use.

Thujone is named after the plant from which it was first extracted, thuja (Thuja occidentalis). Since thujone was also extracted from other plants before its structure was identified, it is also known as absinthol, tanacetone, and salviol. According to IUPAC (International Union of Pure and Applied Chemists) nomenclature, it is officially called 3 thujamone or 3 sabinone (Albert-Puleo 1978). There are two stereoisomers of thujone: (-)-3-isothujone (or

- or l-thujone) and (+)-3-thujone (or

- or d-thujone). Thujone is the major component of wormwood oil and accounts for up to 90% of the oil's weight (Simonsen 1949).

There have been several reports that wormwood has psychoactive effects. In his excellent book, Pharmacotheon, J. Ott writes that he tried smoking dried wormwood leaves and found it had a definite psychoactive effect (Ott 1993). Pendell (1994) repeated this experiment with similar effects. Furthermore, various other species of the Artemisia genus have been smoked and used as intoxicants in other cultures. Artemisia nilagirica is reportedly smoked in West Bengal for its psychoactive effects (Pal and Jain 1989). Similarly, Artemisia caruthii is inhaled by the Zuni as an analgesic (Ott 1993). However, these experiments yield little insight into the active component(s) of wormwood and whether these components play a role in absinthe's effects. For example, despite being smoked for its psychoactive effects, an assay of Artemisia nilagirica oil found it contained less than one percent total thujones (Uniyal, Singh, Shah, and Naqvi 1985).

There are also indications that thujone itself is psychoactive. Rice and Wilson (1976) have found that (-)-3-isothujone, the dominant isomer in wormwood oil, has an antinociceptive (pain killing) effect, comparable to codeine, when injected subcutaneously in rats. Because the effect is stereospecific and not elicited by similar compounds, the researchers suggest that (-)-3-isothujone acts at a specific pharmacological site.

Thujone's mechanism of action is unknown. Structural similarities between thujone (in its delta-3,4 enol form) and tetrahydrocannabinol (THC, the active component in marijuana) have led some to hypothesize that both substances have the same site of action in the brain (del Castillo et al 1975). However, Meschler et al. (1997) recently presented evidence that that neither thujone, wormwood, nor HPLC fractions from oil of wormwood bind to the cannabinoid receptor at physiologically relevant concentrations. This finding confirms earlier but less direct evidence that thujone does not act at the cannabinoid receptor (Greenberg, Mellors, and McGowan 1978, Browne and Weissman, 1981, Rice and Wilson, 1976). It would seem that thujone acts through some other, yet unidentified, mechanism.

Although thujone is apparently psychoactive, there isn't much direct evidence to confirm its importance in absinthe intoxication. Absinthe is approximately 75% alcohol. Therefore, alcohol's effects should limit the amount of thujone one can ingest. Quite simply, you can only drink a moderate amount of thujone before you become very drunk from the alcohol. Thujone would have to be active at a very low dose or be present in high quantities in order to have any appreciable effect.

Arguing against thujone's importance, B. Max, in the "This and That" column in Trends in the Pharmacological Sciences, made the following dose calculations:

Although I agree with his feelings about the literature on thujone's activity, Max may underestimate the possible effects of chronic thujone intake. The reference which he uses to support his claim (Pinto-Scognamiglio 1968) actually did find some indications of an effect from chronic thujone intake. Rats treated with 10 mg/kg/day oral thujone increased their spontaneous activity from 4pm to 8pm (the early part of the nocturnal rats' active period). In addition, a subgroup of 6 slow-learning rats significantly improved (in comparison to controls) their acquisition of a shock avoidance task after 7 days of 10 mg/kg/day oral thujone. However, this effect was not replicable in a larger group of 34 rats. Because these 34 rats were naive to the task and therefore of unknown learning ability, we cannot rule out the possibility that thujone may somehow alter the learning abilities of slow-learning rats but not fast-learners.

The appearance of thujone's effects after chronic administration of an otherwise ineffective dose is consistent with the toxicological data on thujone. In rats, at least, thujone accumulates with regular use. In Margaria's (1963) unpublished rat research (cited in Pinto-Scognamiglio 1967), rats fed 10 mg/kg/day orally accumulated about 5% of the daily dose. On the 38th day of the research, convulsions were evident in the rats. Similarly, in the human data, quoted in the toxicology section below, humans taking thujone-containing essential oils experienced convulsions after taking approximately the same dose of oil for several days without incident (Millet et al 1980).

Thus, there are indications that a large enough dose of thujone will be psychoactive and that thujone can accumulate in one's body. However, this does not prove that accumulated thujone was partially responsible for absinthe's psychoactivity. When chronically exposed to a drug, receptors in the brain often become less sensitive to a drug's effects. The brain of a chronic absinthe user might become tolerant to the slow accumulation of thujone, thus blocking any possible psychoactivity. On the other hand, in some cases, repeated doses of drugs can cause hypersensitivity. It is also possible that this occurred with absinthe drinkers. This is just speculation. The toxic effects of repeated thujone ingestion are more definite.

In summary, thujone seems psychoactive although probably not by acting at the cannabinoid receptor. Small ineffective doses may accumulate in the body to the point of having psychoactive and toxic effects. If this is the case, it validates absinthe's reputation for producing an unusual intoxication. Still, this reputation mostly dates to the beginning of the century or earlier, a time when medicine and science were very different from today. Lacking more recent research on thujone and absinthe, it seems reasonable to take reports of absinthe's uniqueness with skepticism. Thujone may play a role in absinthe, but the evidence is not conclusive. Finally, it should be noted that by focusing on one component of wormwood oil, we ignore the many other poorly characterized compounds in wormwood and absinthe's other herbal ingredients which may play some role in absinthe's intoxicating and toxic effects.