The EclecticPhysician

The Eclectic Physician
Medicinal Herb Monographs

St Johnís Wort

Botanical Name 
Hypericum perforatum

Hypericum perforatum
(St.John's Wort)

The information on this page compiled by
Beth Burch N.D.
(click on the keywords)


St. Johnís Wort has a long history of use for a variety of conditions. Kingís American Dispensatory lists its actions as sedative, astringent and diuretic useful for nervous affections with depression, hemorrhages, diarrhea and chronic urinary tract problems. It is specific for spinal injuries and is used externally for bruises, wounds, ulcers and tumors. Weissí Herbal Medicine states it is useful as an antidepressant , as well as treatment of bed wetting (enuresis) and night terrors in children. Recent research has confirmed that St. Johnís Wort is an effective antidepressant with few side effects.


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  • St. Johnís Wort is Hypericum perforatum, a beautiful plant which flowers around the summer solstice, hence its name, for St. Johnís day, June 24. It is a perennial, found in disturbed areas and considered a noxious weed in many parts of the US. It grows 1-3 feet tall with small oval leaves with tiny dots. When held up to the light these glands make the leaf appear perforated, thus the species name. The flowers are a deep bright yellow, about an inch in diameter with five petals. The petals have numerous black dots, containing a red pigment. The upper tops of the flowering plant are the medicinal part.


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  • Contains at least 10 constituents or groups of constituents that may contribute to its effects.
  • Hypericin complex, including hypericin, pseudo-hypericin, isohypericin & protohypericin
  • Flavonoids including hyperoside, quercitin, rutin & biflavones
  • Hyperforin-a phloroglucinol derivative
  • Volatile oils including n-alkanes, a-pinene and other monoterpenes
  • Tannins
  • Procyanidins


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  • Antidepressant/Sedative- Experimental studies have shown that hyperforin exhibits serotonin reuptake inhibition (1,2)
  • Anti-inflammatory
  • Anti-bacterial
  • Indications
  • Internally-
  • Mild to moderate depression (3,4,5)
  • Externally-
  • Wounds, bruises, burns
  • Myalgia (muscle pain).


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  • Dry extract or freeze-dried- Look for an extract assayed for hyperforin content, 300 mg one to three times a day
  • Liquid Extract- 1:1 made with fresh plant- 1/4-1/2 teaspoon one to three times a day
  • Take with food to minimize possible gastrointestinal upset
  • May take 4-8 weeks to get optimal effects. Assess the response after 6 weeks and adjust dosage at that time. If no response after 6 weeks, consult a physician.


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Side Effects

  • Gastrointestinal upset
  • Allergic reactions
  • Dizziness
  • Tiredness/Fatigue
  • Restlessness
  • All side effects are completely reversible- stop taking the St. Johnís Wort and side effects go away
  • May cause a photosensitivity reaction in some people- use sunscreen and avoid sun exposure while taking St. Johnís Wort.


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  • Severe depression (with suicidal, psychotic, or severe melancholic symptoms)
  • Bipolar depression (manic-depressive illness)

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Interactions with medications

  • Donít combine with prescription antidepressants (6,7)
  • May interfere with iron absorption (7)

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Use in pregnancy & lactation

  • No information on the safety of use in pregnancy or lactation
  • It is known that St. Johnís Wort inhibits pituitary secretion of prolactin, so the possibility exists that there could be problems with breast milk production

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1. Singer A et al, Hyperforin, a major antidepressant constituent of st. John's wort, inhibits
serotonin uptake by elevating free intracellular Na, J Pharmacol Exp Ther 1999;290(3):1363-8
2. Chatterjee SS et al, Hyperforin as a possible antidepressant component of hypericum extracts, Life Sci 1998;63(6):499-510
3. Laakmann G, St. John's wort in mild to moderate depression: the relevance of hyperforin for the clinical efficacy, Pharmacopsychiatry 1998;31 Suppl 1:54-9
4. Lenoir S et al, A double-blind randomized trial to investigate three different concentrations of a standardized fresh plant extract obtained from the shoot tips of Hypericum perforatum, Phytomedicine 1999;6(3):141-6
5. Josey ES et al, St. Johnís wort: a new alternative for depression?, Int J Clin Pharmacol Ther 1999;37(3):111-9
6. Lantz MS et al, St. John's wort and antidepressant drug interactions in the elderly, J Geriatr Psychiatry Neurol 1999;12(1):7-10
7. Miller LG, Herbal medicinals: selected clinical considerations focusing on known or potential drug-herb interactions, Arch Intern Med 1998;158(20):2200-11
8. Ernst E et al, Adverse effects profile of the herbal antidepressant St. Johnís wort (Hypericum perforatum), Eur J Clin Pharmacol 1998;54(8):589-94

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* The information presented in this web site is intended to inform and educate. It is not intended replace a qualified medical practitioner to diagnose or treat medical conditions.

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