St John's wort

Hypericum perforatum, Hypericaceae. The aerial parts of the plant are used.

The entire plant above the ground should be gathered when in flower and dried as quickly as possible.

Functions of St John's wort

St John's wort has long been a valued herb. It:

  • has a sedative and pain reducing effect which makes it useful in reducing tension, anxiety and generally lifting the spirits. It is considered a specific herb for emotional problems during menopause. Its sedative effect has been attributed to hypericin, which reduces blood pressure, capillary fragility and benefits the uterus.
  • can be used for heavy, painful and irregular periods as well as premenstrual syndrome.
  • has a diuretic action which reduces fluid retention and enhances the removal of toxins.
  • has an expectorant action, clearing phlegm from the respiratory tract.
  • has an antibacterial and antiviral action and is being researched for its effectiveness as a treatment in TB, HIV, AIDS as well as various cancers.
  • contains astringent properties and also because of it antimicrobial action it can be used in cases of gastroenteritis, diarrhea and dysentery. It is also said to heal peptic ulcers and gastritis.
  • can be used as a remedy for nerve pain including trigeminal neuralgia, sciatica, fibrositis, back pain, headaches and shingles. As a lotion it will speed the healing of minor burns (such as mild sunburn), cuts, sores and ulcers.

Notes on St John's wort

  • This herb can cause sensitivity to sunlight.
  • When taken internally this herb can cause stomach upset, dizziness and fatigue.
  • St John's wort reacts with some medications (including warfarin, immuno-suppressant drugs, some HIV and anti-epileptic medications and other antidepressants). So always check with your health professional before taking this herb.
  • It increases the production of liver enzymes that break down medications. This means that it can decrease the effectiveness of some medications, including the contraceptive pill.
  • It is not recommended that it be used in cases of marked depression.
  • If using the herb for its mood-elevating effects you need to be patient as it takes 4 to 6 weeks to take effect.


Infusion: pour a cup of boiling water onto 1-2 teaspoonsful of the dried herb and leave to infuse for 10-15 minutes. This should be drunk three times per day.

Tincture: take 1-4 ml of the tincture three times per day.

For the gardener

St John's wort is a short lived perennial that may need to be replanted every few years.

They need a well drained soil and prefer full sunlight, but they will tolerate part shade. Place the seedlings about 24 inches (60 cm) apart with 24 inches (60 cm) between the rows. Water regularly during the first year.


Duke, J. A. 2000, Anti-aging Prescriptions. Rodale.

Hoffmann, D. 2000, The New Holistic Herbal. Element Pub.

Hoffmann, D. 2001, Healthy Bones and Joints. Newleaf.

McIntyre, A. 1995, The Complete Women's Herbal. Henry Holt Reference Books.

Mills, S. Y. 1989, The A-Z of Modern Herbalism: A Comprehensive Guide to Practical Herbal Therapy. Thorson.




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