Calm Teas

Herb record · Hypericaceae

St John's wort in tea: cautions and interactions

Reviewed

Not a typical tea herb, but it turns up in some 'calm' blends. It weakens many prescription drugs, including birth control, so it's the most important flag in this index.

Yellow five-petalled St John's wort flowers
Photo: Krzysztof Ziarnek, Kenraiz, Wikimedia Commons, CC BY-SA 4.0. Cropped to 3:2, resized and converted to WebP (adaptation shared under the same license).

At a glance

Latin name
Hypericum perforatum
Evidence
Caution ingredient Listed for its safety profile rather than calming evidence.
EU tea amount
The EU monographs we use list no tea preparation for this herb.
Cautions
St John's wort: weakens many medicines
In our index
1 tea

Who should be careful with st john's wort?

  • St John's wort: weakens many medicines. Can weaken many medicines, including some antidepressants, birth control pills, cyclosporine, some seizure, heart, HIV and cancer drugs, warfarin and certain statins. With serotonin-affecting drugs it may cause serious side effects. (NCCIH fact sheet)(Asher et al., 2017)

This list repeats what the cited sources say; it isn't a complete interaction check. A pharmacist can check your specific medicines.

Which calming teas contain st john's wort?

Sources

  1. NCCIH (NIH). St. John's Wort, updated May 2025.
    Government fact sheet
    Can weaken the effects of many medicines, including some antidepressants, birth control pills, cyclosporine, some seizure, heart, HIV and cancer drugs, warfarin and certain statins. With serotonin-affecting drugs it may cause serious serotonin-related side effects.
    checked against the official page, 2026-10-21
  2. Asher et al. (2017). Common Herbal Dietary Supplement-Drug Interactions. Am Fam Physician.
    Review · form: supplement
    Clinical review of herb–drug interactions. St John's wort and goldenseal cause clinically important interactions; valerian is listed among supplements with a low likelihood of interactions.
    Limits: About supplements; 2017.
    checked against the abstract, 2026-10-21 · PMID 28762712