Gaia Herbs | plant intelligence

St. John's Wort


This plant is native to Europe but has been naturalized in most of the northern hemisphere. The name refers to the fact that it flowers around the feast of Saint John on June 24th which is also close to the summer solstice. A plant that is common to waste areas, roadsides, and fields it has a rich and colorful tradition of usage dating back to ancient Greece. Gaius Plinius Secundas (Pliny the Elder) wrote about this plant in his 37 volume Natural History which served as the basis of scientific knowledge for centuries. In Greek it is called hypericon (above the icon) referring to its power “over the image” and this idea was furthered through the years. The European peasants thought the plant protected them from evil spirits, witches, demons and lightning.


There have been hundreds of randomized controlled studies on St. Johns Wort Extract. The majority do favor a positive effect on mood, particularly when whole plant extracts are used. The flavonoids hypericin and hyperforin have been the most lauded chemicals contained in St. Johns Wort that may be responsible for its pharmacological activity; yet with all the research, it is still unclear which chemicals, if any, are responsible for its activity. The flowers contain many antioxidants such as Rutin, Quercetin, and Lutein. One of the best reviews published in Phytomedicine in 2002 compiled results from 34 controlled, double blinded studies on over 3000 patients and found positive results when using between 300 and 1000 mg of extract per day. More research is needed to determine the exact mechanism of therapeutic action in this plant.

Uses of St. John's Wort


This information in our Herbal Reference Guide is intended only as a general reference for further exploration, and is not a replacement for professional health advice. This content does not provide dosage information, format recommendations, toxicity levels, or possible interactions with prescription drugs. Accordingly, this information should be used only under the direct supervision of a qualified health practitioner such as a naturopathic physician.

Active Constituents

Flavonoids such as hypericin and hyperforin and antioxidants such as Rutin, Quercetin, and Lutein

Parts Used

  • Flower buds

Important precautions

Do not take with antidepressant medication

Additional Resources

Lecrubier Y, Clerc G, et al. AM Journ. Psychiatry. 2002 Aug;159(8):1361-6.

Behnke K., Jensen GS., Graubaum HJ., Gruenwald J., Advances in Therapy. 2002 Jan-Feb;19 (1):43-52.

Barnes J., Anderson LA, Phillipson JD. J Pharm. Pharmacol. 2001 May;53(5):583-600.

Schulz V., Phtomedicine. 2002 July;9(5):48-74.

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