Sweet Wormwood

• Do not use the tea or herb to treat or prevent malaria. WHO does not support using Artemisia plant material in any form, including tea, to prevent or treat malaria. Content of the active compound varies and is often too low to clear all parasites, so the infection can return. WHO also warns widespread herbal use could speed artemisinin resistance, which would weaken the prescription medicines millions rely on. A traveller developed severe malaria despite regular tea. Seek medical care for any fever after being in a malaria area. Authoritative guidance ^{20 9 1 15}
• Liver injury has been reported with both tea and an extract supplement. A 2019 case report links the tea to severe cholestatic hepatitis (jaundice) in a traveller, with a probable causal score. New Zealand's regulator received 25 liver-harm reports tied to one extract supplement, with an estimated 0.5 to 6.3 cases per 10,000 consumers; most people recovered after stopping. One of 14 people on the higher dose in the pilot trial developed hepatitis. Stop and get medical help for jaundice, dark urine, pale stools, itching or belly pain. Case report ^{17 7 18 12}
• Pregnancy, breastfeeding and young children: no safety data for the herb. A 2026 review says safety data for the tea are critically insufficient in children under five, pregnancy, breastfeeding and liver or kidney disease. This is missing evidence, not proof of safety. WHO's first-trimester position, as reported by secondary sources, concerns a prescription artemisinin medicine given under medical care, not the herb. Authoritative guidance ^{15 19}
• Possible interaction with medicines cleared by liver enzymes (lab evidence only). MSK reports that lab studies show Artemisia extracts induce the liver enzymes CYP2B6 and CYP3A4, which clear many medicines, and says clinical relevance is unknown. A 2022 liver-cell study found pure artemisinin increased these enzymes, but teas blocked enzyme activity instead. No human interaction study was found, so the direction in people is unknown. Laboratory research ^{8 6}
• Tea strength varies, and the herb is not the same as the drugs. One litre of tea in a volunteer study held about a fifth of a usual daily drug dose of artemisinin, and content changes with plant and brewing. The prescription medicines (artemisinin, artesunate) are purified, dosed products with their own side effects, including hearing problems and delayed anaemia, which should not be assumed for the herb. Pharmacokinetic ^{16 21 8}

Liver harm is the best-documented risk of the herb products. A tea user developed severe cholestatic hepatitis (RUCAM 'probably'). Medsafe received 25 reports linked to one Artemisia annua extract (6 hepatocellular, 7 cholestatic, 3 mixed, one cirrhosis, 8 unknown pattern); most were recovering after stopping. LiverTox's entry for artemisinin, as summarised secondhand, scores it D (possible rare cause) with most cases involving A. annua products; we could not open the page. ^{17 7 12 18}

How often. Medsafe's estimate is 0.5 to 6.3 cases per 10,000 consumers of one extract; no rate is available for tea.

Monitoring. Medsafe advises stopping the product and seeing a doctor for nausea, belly pain, pale stools, dark urine, itching or jaundice. No routine blood-test schedule was found.

• . Traveller with severe cholestatic hepatitis after Artemisia annua tea for malaria prevention; bilirubin normal at 3 months. ¹⁷
• . 25 NZ reports with one extract supplement (to 30 Sept 2018). ⁷

This is a safety connection. It is not evidence that Sweet Wormwood supports liver health.

Summary. We found no toxic-dose figures for the herb in the sources read. Known harms are liver injury reports and, for the drugs, hearing problems and delayed anaemia. Neurotoxicity of artemisinin has been raised in animal work, but we did not read that literature and found no human herb case.

Animal. Not reviewed; we did not read animal toxicity papers.

Human doses studied. Not given here.

High dose or long term signals. The higher-dose arm in the osteoarthritis pilot showed one hepatitis case and no benefit; the six-month extension was reported as well tolerated.

Overdose response. No overdose report was found.

Genotoxicity. Not checked.

Toxic plant parts. No toxic-part warning was found for the leaves.

Main quality problem is variability: artemisinin content differs between plants, cultivars and brewing. No heavy-metal or pesticide testing of products was found in the sources read. Do not confuse with other Artemisia plants.

Variable artemisinin content. WHO says artemisinin content varies substantially between herbal products. Brewing temperature strongly changes how much reaches the tea. ^{20 21 16}

Different Artemisia species. Wormwood (A. absinthium), mugwort and African wormwood (A. afra) are different plants. A. afra tea in the cell study had almost no artemisinin. ⁶

Supplements with other ingredients. One co-suspected product in the Medsafe alert was a different product, so labels and ingredients matter. ⁷

• Fever, chills or flu-like illness within months of travel to a malaria area: seek medical care the same day.
• Yellow skin or eyes, dark urine, pale stools, itching or belly pain: stop the product and get medical help.
• New ringing in the ears, hearing loss or marked dizziness after artemisinin-type medicines: tell the doctor.
• Unusual tiredness, pale skin or dark urine weeks after malaria drug treatment: tell the doctor (delayed anaemia).

Stop the supplement and contact a clinician or emergency service. In the US, Poison Control is 1-800-222-1222.