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Western herbalism

WormwoodArtemisia absinthium

Very bitter European herb. Two small Crohn disease studies used 3 x 500 mg and 3 x 750 mg a day; no human parasite trial found. The EU lists it for appetite only.

Botanical name
Artemisia absinthium
Part used
leaf and flowering top (herb)
Also called
Absinthe wormwood, Absinthii herba (pharmacopoeia name)
Used in
Western herbalism
Taken for
Appetite, Indigestion, Antimicrobial use
Sold as
tea, tincture, capsules, powder, fresh

What wormwood is

Wormwood, Artemisia absinthium, is a silvery, strongly aromatic perennial of the daisy family. The leaves and flowering tops are the part used. It is strongly bitter, and it is the major component that gives absinthe its character, as Lachenmeier and colleagues describe in their review of that spirit. It is not the same species as sweet wormwood (Artemisia annua), the source of the malaria drug artemisinin, and findings for one do not transfer to the other.

Wormwood is prepared as a tea from the dried herb, as an expressed juice from the fresh plant, as a tincture, as a powder in capsules and as an essential oil. The EU herbal monograph covers the dried herb as tea or powder, the juice and the tincture, not the oil. In supplements it is the bitter component in digestive bitters and one of the herbs in antimicrobial and parasite-cleanse blends.

The plant contains thujone, a compound described by Lachenmeier and colleagues as a toxic monoterpene and one that is regulated in alcoholic drinks. This is the main reason wormwood is handled with more caution than most bitter herbs.

What the traditions use it for

Western herbalism

European herbal tradition treats wormwood as a bitter: a plant taken for its taste to stimulate appetite and digestion. The EU herbal committee (HMPC) accepts two traditional uses, based on long-standing use and not on trials: temporary loss of appetite, and mild dyspeptic or gastrointestinal disorders. The EU also lists wormwood among the herbs allowed in bitter herbal tea blends for loss of appetite, alongside gentian, yarrow, dandelion root, centaury and others.

The constituents

The bitterness comes from sesquiterpene lactones such as absinthin, and the essential oil carries thujone. In a guinea-pig tissue study of a nine-herb bitter blend containing wormwood and gentian, the blend relaxed stomach muscle by blocking the M2 muscarinic receptor, but the individual components that blocked that receptor were juniper, masterwort and sage, not wormwood or gentian. In sheep naturally infected with worms, a wormwood extract at 1.0 g/kg reduced egg counts, with therapeutic success in 76.77 percent against 100 percent for albendazole. These are laboratory and animal findings.

The human evidence

The human trials are in Crohn’s disease, not in the digestive complaints the herb is traditionally used for. Omer and colleagues randomized 40 people with Crohn’s disease (20 per group) who were taking steroids to a herbal blend containing wormwood herb (3 x 500 mg a day) or placebo for 10 weeks while the steroid was tapered. After 8 weeks 13 of 20 (65 percent) on wormwood were in almost complete remission against none on placebo, and steroids had to be restarted in 2 (10 percent) on wormwood against 16 (80 percent) on placebo. It was a blend, so the effect cannot be credited to wormwood alone.

Krebs and colleagues gave 10 people with Crohn’s disease 3 x 750 mg a day of dried wormwood powder for 6 weeks on top of their usual treatment and compared them with 10 controls. Serum TNF-alpha fell from 24.5 to 8.0 pg/ml against 25.7 to 21.1 in controls, and remission occurred in eight people against two. Both studies were small, and we found no larger independent trial that confirmed either.

For the traditional uses, we found no randomized trial of wormwood alone for appetite or dyspepsia; the EU monograph rests on long-standing use. For parasites we found no human trial of Artemisia absinthium. In the retrospective Chedid series for small intestinal bacterial overgrowth, one of the commercial herbal formulas contained an Artemisia absinthium extract along with other herbs; 17 of 37 people (46 percent) on herbal therapy had a negative breath test against 34 percent on rifaximin, and wormwood cannot be isolated from that result.

The traditional uses and the parasite use have no placebo-controlled trial of wormwood behind them that we could find.

StudyDoseWhat it found
Double-blind randomized trial, 40 people with Crohn's disease on steroids PMID 17240130Herbal blend containing wormwood herb, 3 x 500 mg a day for 10 weeksNear-complete remission at 8 weeks in 13 of 20 (65%) vs 0 on placebo; steroids restarted in 2 vs 16
Controlled trial, 20 people with Crohn's disease (10 vs 10) PMID 199622913 x 750 mg a day of dried wormwood powder for 6 weeksTNF-alpha 24.5 to 8.0 pg/ml vs 25.7 to 21.1 in controls; remission in 8 vs 2
Retrospective series, 104 people with SIBO; herbal formulas (one containing wormwood extract) vs rifaximin PMID 248919902 capsules twice daily for 4 weeks (commercial formulas)Negative breath test in 17 of 37 (46%) on herbals vs 23 of 67 (34%) on rifaximin, not significant

Doses, in trials and in practice

The EU monograph for the traditional uses lists, for adults, a tea of 1 to 1.5 g of cut herb in 150 ml of boiling water per dose (2 to 3 g a day), taken 30 minutes before meals for appetite or after meals for dyspepsia; or powder at 0.76 g per dose (2.28 g a day); or expressed juice at 5 ml per dose (10 ml a day); or tincture at 1 g per dose (3 g a day). The Crohn’s studies used 3 x 500 mg a day of a blend and 3 x 750 mg a day of powder. The monograph says to consult a practitioner if symptoms last more than 2 weeks.

The amounts above are what trials and pharmacopoeias record, not a dose for you; your medicines and conditions change the answer, and a clinician or pharmacist who knows them is the person to ask.

What is known about safety

The EU monograph reports no side effects at the time of assessment but lists contraindications: allergy to wormwood or other plants of the daisy family (Asteraceae), bile duct obstruction, cholangitis and liver disease, and it advises people with gallstones or other biliary disorders to consult a doctor. It states that use under 18 years of age has not been established and that use in pregnancy and breastfeeding is not advised because data are limited, and it carries an alcohol warning for tinctures. Thujone is the main toxicological concern, as discussed in the absinthe review by Lachenmeier and colleagues, and the EU bitter-tea monograph requires daily thujone exposure from blends containing wormwood to be below 6.0 mg. We found no study of the heavy-metal content of wormwood supplements.

Where it meets prescription medicines

The EU monograph states that no interactions with medicines have been reported. We found no formal interaction study of wormwood in people. Because the monograph contraindicates use in liver disease, it is a point to raise for anyone taking medicines that already tax the liver; that reasoning comes from the contraindication, not from a documented interaction.

Medicines the site’s own interaction rules flag with wormwood

The quiz applies these rules when someone names a medicine. They come from published interaction references and are a reason to ask a pharmacist, not a diagnosis:

Catalog entries that list wormwood

If you want wormwood in a product rather than as a loose herb, these are the entries that carry it, with the label amounts and the reviews read.

Gundry MD Total Restore 4.1 out of 5 from 9,333 ratings from Amazon · $2.33 a day NOW Foods Green Black Walnut Wormwood Complex 4.4 out of 5 from 4,921 ratings from Amazon · ~$0.48 a day at the full label dose, about $0.12 at the lowest Renew Life PARA SMART Cleansing Formula, 15-Day Program 4.2 out of 5 from 1,398 ratings from Amazon · ~$2.04 a day across the full 15-day program

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Herbs that sit beside it

Western Gentian Gentiana lutea Western Quassia Quassia amara; Picrasma excelsa Western Yarrow Achillea millefolium Western / TCM Dandelion Taraxacum officinale (and T. mongolicum in Chinese medicine)

What people want to know

Is there a human trial of wormwood for intestinal parasites?

We found none for Artemisia absinthium. The evidence is laboratory work and a study in 18 sheep, where an extract reduced worm egg counts with a therapeutic success rate of 76.77 percent against 100 percent for albendazole. Sweet wormwood (Artemisia annua) is a different plant.

What do the Crohn’s disease studies show?

In a 40-person double-blind trial, a herbal blend containing wormwood was followed by near-complete remission at 8 weeks in 13 of 20 people against none on placebo. A second 20-person study found remission in eight of 10 against two of 10 controls. Both are small and the first used a blend, so they are early findings, not settled evidence.

Is wormwood tea the same as absinthe?

No. Absinthe is a spirit flavored with wormwood and other herbs. The EU monograph covers wormwood as a tea, powder, juice or tincture, and does not cover the essential oil.

Who is advised against wormwood?

The EU monograph contraindicates it with allergy to wormwood or other Asteraceae plants, bile duct obstruction, cholangitis or liver disease. It says use under 18 has not been established and that use in pregnancy and breastfeeding is not advised.

Sources