St. John’s wort (Hypericum canadense)

St Johns wort

Common Name

  • Irish St. John’s-wort
  • Lesser Canadian St. Johnswort
  • Canada St. John’S Wort
  • Canada St. John’S-Wort
  • Irish St John’S-Wort
  • Canadian St. John’S Wort
  • Lesser Canada St. John’S-Wort


Clusiaceae (St. John’s wort/ garcinia/mangosteen)

Parts used

Flowers and leaves

BOTANICAL description

St. John’s wort is a low-lying herb measuring 30-75 cm. in height. Flowers: The radially symmetrical flowers of St. John’s wort are small, measuring 2-2.5 cm. in width. The blooms have five rounded petals with distinctive black spots, numerous stamens, and 3 styles. Flowers are arranged singly atop the terminal shoot of the stem. Leaves: The leaves are small, measuring 2.5-5 cm. in length and are light green and elliptical with distinctive, translucent spots/irregularities. Leaves are arranged in an opposite fashion along the length of the stem.


St. John’s wort grows best in fields, along roadsides, and around wet areas. It’s cousin (Hypericum perforatum) is native to temperate zones of Europe and Western Asia; naturalized in the Americas and Australia. In open situations on semi-dry calcium rich soils.

Edible Uses/Preparation

The leaves were once used as a salad greens and an alcoholic extract can be used to dye silk and wool(only) a violet red.

Medicinal Uses/Key Actions

Vulnerary- lightly diuretic, sedative, anti-inflammatory, anti-diarrhoeic, cholagogue, antidepressant, antiviral, antibiotic, and astringent. Systems affected: Liver, Nervous system, and lungs. Excellent to relieve symptoms of anxiety, depression, seasonal affective disorder, PMS, menopause and sometimes insomnia. Can be affective on nerve pain, lower back, rheumatism, arthritis, and chronic inflammation. The plant constituents are; Volatile oil called red oil- a resin, red pigmented glycoside, hypericine, a polyphenolic flavonoid, hyperoside, tannin (8-9% in the whole plant and 16% concentrated in the flower) carotene, and vitamin C.

Contra-indications; can cause photosensitivity or increase other allergies in both human and animals if taken in excess. Do not take with other antidepressant medication as it will decrease ( and sometimes nullify) the effectiveness of both. Do not use with narcotics, alcohol, cold or hay fever medications, birth control, tryptophan, or tyrosine. Do not use during pregnancy.

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