← The ApothecaryLamiaceaeaerial partsFact-checked 24 October 2026

Significant riskGermanders (Teucrium) are a recognised cause of herb-induced liver injury: their neo-clerodane diterpenoids are activated by CYP3A to toxic metabolites. Three Turkish women who took T. polium powder for 40 days to 3 months in late pregnancy or after birth developed jaundice with ALT up to about 2,400 IU/L; liver tests returned to normal within 3 months of stopping, and two had had similar episodes with earlier use. An Iranian woman who drank three 200 ml cups of the decoction developed severe haemolysis (haemoglobin fell to 4.7 within 12 hours) and acute kidney failure. A Syrian diabetic woman developed ketoacidosis, liver and kidney injury and heart block after a week of heavy use, and died.In an emergency, call your local emergency number or poison centre.

Felty germander

Teucrium polium

Also calledMountain germander

A grey, woolly Mediterranean and Middle Eastern mint-family herb, widely drunk as a tea for diabetes, stomach complaints and wounds. Germanders as a group are known to cause liver injury, sometimes severe or fatal, and T. polium has its own case reports of hepatitis, kidney failure and haemolysis.

What it is used for

Blood sugar and diabetes
Limited
Taken as tea for diabetes in Syrian, Turkish and Iranian folk medicine, and blood-sugar lowering is reported mainly in animal studies. No controlled trial of oral use in people was found. A Syrian woman who stopped insulin and drank three large cups a day for a week developed diabetic ketoacidosis, liver and kidney injury and complete heart block, and later died.^2,3,4
Wounds and cuts
Limited
Used in Iranian folk medicine for diabetic ulcers. In a placebo-controlled trial (70 enrolled, 55 completed), adding T. polium ointment to standard care for 4 weeks shrank non-infected diabetic foot ulcers more than placebo ointment.⁶
Mouth ulcers and gum health
Limited
In a small double-blind crossover trial in 22 dental students, a mouthwash containing an aqueous T. polium extract lowered salivary Streptococcus mutans counts compared with the same mouthwash without it.⁷
Indigestion and dyspepsia
Traditional
Tea and powder are used for gastrointestinal complaints in Middle Eastern and Turkish folk medicine; no trials were found.^2,4
Breast-milk supply
Traditional
In Turkey it is used in late pregnancy and after birth to increase breast milk. Three women who took it for this reason developed serious hepatitis (see safety).²

How it is prepared

infusion

Aerial parts soaked or boiled in hot water and drunk as tea. Case reports describe serious poisoning after about three large cups a day for a week, and after three 200 ml cups taken at once.

powder

Dried powdered herb taken by spoon. In the Turkish case series the women took 2–3 tablespoons of dry powder a day for 1–3 months before developing hepatitis.

Amounts are as recorded by the named source, not a recommendation.

Safety

Pregnancy: Avoid
Breastfeeding: Avoid

Interactions with medicines

insulin and other diabetes drugsMajorA patient who replaced insulin with T. polium tea developed fatal complications including diabetic ketoacidosis; the herb is not a substitute for prescribed treatment.

Interaction checker →

Do not use if

Liver disease
Pregnancy and the postpartum period (case reports of severe hepatitis)

Side effects

Hepatitis with jaundice
Acute kidney injury
Haemolysis
Complete heart block (single case report)

In the healing traditions

Middle Eastern
Teucrium polium (mountain germander)
Tea or powdered aerial parts for diabetes, high blood fats, gastrointestinal complaints, blood pressure, urinary infections, headache and wounds (Syria, Turkey, Iran). In Turkey it is taken in the last months of pregnancy and after childbirth for digestion and to increase breast milk; an Iranian case report describes a large dose taken with the intention of causing abortion.

Active compounds

neo-clerodane (furano-)diterpenoids: oxidised by CYP3A into reactive metabolites that deplete liver glutathione and kill liver cells; the accepted mechanism of germander hepatotoxicity
poliumoside, verbascoside: phenylethanoid glycosides reported in the aqueous decoction

History

Germanders have been used for centuries in herbal teas; more recently germander extracts were marketed for weight control, diabetes and high cholesterol, and these were linked to multiple cases of liver injury (LiverTox). The mechanism was worked out mainly for wall germander (T. chamaedrys). T. polium remains a popular folk remedy for diabetes in Syria, Turkey and Iran.

Sources

Reference, not prescription. Nothing here is medical advice. Herbs can interact with medicines and be dangerous in pregnancy; tell your doctor or pharmacist about anything you take.