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St John's wort

Hypericum perforatum

Also calledJohanniskraut (German) · Hierba de San Juan (Spanish) · Millepertuis (French) · Hufariqun / Hyperikon (Arabic / Greek)

A yellow-flowered meadow herb whose extracts have the best evidence of any herbal antidepressant: for mild to moderate depression they work better than placebo and about as well as standard antidepressants. It is also one of the most dangerous herbs for drug interactions, because it speeds the breakdown of many medicines, including the contraceptive pill, transplant drugs, HIV drugs and warfarin.

Full natural-history sheet →

What it is used for

  • A Cochrane review of 29 trials (5,489 patients) found the extracts tested were better than placebo for major depression, about as effective as standard antidepressants, with fewer side effects; results were more favourable in German-speaking countries. EMA accepts specified extracts as well-established use for mild to moderate depressive episodes. It is unclear whether it helps severe depression. Depression needs medical assessment.1,2,3

  • Menopause
    Limited

    A small number of studies suggest it may help hot flushes (NCCIH).2

  • EMA traditional use of certain preparations for temporary mental exhaustion.1

  • Sleeplessness
    Traditional

    EMA traditional use of the herbal tea as supportive treatment for nervous restlessness with difficulty falling asleep.1

  • EMA traditional use for symptomatic relief of mild gastrointestinal discomfort.1

  • Wounds and cuts
    Traditional

    EMA traditional use of the oil extract (the red 'St John's oil') or tincture on the skin for minor inflammation such as sunburn and to aid healing of minor wounds; NCCIH notes wound-healing research has not clearly shown benefit.1,2

How it is prepared

dry extract / capsule

Standardised dry extracts in tablets or capsules; only the specific tested extracts carry the clinical evidence, and products vary considerably.

EMA monograph (Rev. 1, 2023), well-established use, e.g. methanolic extract (DER 3–7:1): 300–600 mg 1–3 times daily (600–1,800 mg/day); effect expected within 4 weeks. Not under 18.

Low mood and depression

infusion

Pour 150 ml of boiling water over the cut dried herb and steep.

EMA monograph (Rev. 1, 2023), traditional use: 1.5–2 g in 150 ml, 2–3 times daily (3–6 g/day) for mental exhaustion; 2–3 g twice daily for restlessness and sleep; see a doctor if symptoms last over 2 weeks.

Fatigue and convalescence · Sleeplessness

infused oil

Flowering tops macerated in vegetable oil until it turns red, applied undiluted to the skin.

EMA monograph (Rev. 1, 2023): cutaneous use of the undiluted oily preparation; not under 12; avoid strong sun on treated skin.

Wounds and cuts · Burns and sunburn

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

Safety

Pregnancy
Avoid
Breastfeeding
Avoid
Children
EMA: oral use not recommended under 18; cutaneous use not under 12.

Interactions with medicines

  • hormonal contraceptivesMajorLowers hormone levels: breakthrough bleeding and reduced contraceptive protection. EMA advises additional contraception.
  • ciclosporin, tacrolimus, sirolimus, everolimusMajorLowers blood levels of transplant drugs; risk of rejection. Contraindicated (EMA).
  • HIV protease inhibitors and NNRTIs (indinavir, fosamprenavir, nevirapine)MajorLowers drug levels; risk of treatment failure and resistance. Contraindicated (EMA).
  • warfarin and other coumarinsMajorReduced anticoagulant effect. Contraindicated (EMA).
  • cancer drugs (irinotecan, imatinib, docetaxel and others metabolised by CYP3A4)MajorLower drug levels; reduced effect. Contraindicated (EMA).
  • SSRIs and other serotonergic drugs (sertraline, paroxetine, buspirone, triptans)MajorAdditive serotonergic effects; rarely serotonin syndrome (sweating, fast heart, fever, agitation, tremor).
  • digoxin, ivabradine, simvastatin, alprazolam, midazolam, methadone, amitriptyline, phenytoin, carbamazepineModerateLower plasma levels possible through enzyme and P-glycoprotein induction; effect wears off within about a week of stopping.
  • anaestheticsModerateEMA: possible interactions should be identified before elective surgery and the herb stopped if necessary.
Interaction checker →

Do not use if

  • Use with any of the drugs above without a doctor's supervision
  • Severe depression or suicidal thoughts (needs medical care)
  • Strong UV exposure or light therapy during treatment

Side effects

  • Photosensitivity and skin reactions after sun exposure
  • Digestive upset, diarrhoea
  • Dizziness, restlessness, trouble sleeping
  • Infant colic, drowsiness and lethargy reported in breastfed babies (NCCIH)

In the healing traditions

  • European folk medicine

    Johanniskraut / St John's wort

    Gathered around St John's Day (24 June); the flowers macerated in oil give a red oil used on wounds, burns and aching nerves, and the tea was taken for melancholy and restlessness.

  • Ancient Greek medicine

    Hyperikon

    Described by Dioscorides among wound and urinary remedies.

    Dioscorides, De materia medica III

  • Modern pharmacology

    Hyperici herba extract (e.g. LI 160, WS 5570, Ze 117)

    Standardised dry extracts prescribed, especially in Germany, for mild to moderate depression.

Active compounds

hyperforin
phloroglucinol; thought to contribute to antidepressant action and the main driver of CYP3A4/P-glycoprotein induction
hypericin and pseudohypericin
red naphthodianthrones; cause photosensitivity
flavonoids (hyperoside, rutin, quercetin)

History

The plant's name links it to the feast of St John the Baptist at midsummer, when it flowers. Translucent oil glands make the leaves look pricked with holes, hence perforatum. In Germany standardised extracts became widely prescribed for depression, and the recognition that it lowers blood levels of many drugs made it the textbook example of a herb–drug interaction.

Sources

  1. 1.EMA/HMPC: European Union herbal monograph on Hypericum perforatum L., herba, Revision 1 (EMA/HMPC/7695/2021)
  2. 2.NCCIH: St. John's Wort (fact sheet)
  3. 3.Linde K, Berner MM, Kriston L. St John's wort for major depression. Cochrane Database Syst Rev 2008
  4. 4.EMA/HMPC: Assessment report on Hypericum perforatum L., herba, Revision 1
  5. 5.EMA: Hyperici herba – herbal medicinal product (summary page)

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.