Brought to the New World by early colonists, St. John's wort (Hypericum perforatum) grows readily in sunny pastures and fields, and along rural roadways. The Gale Encyclopedia reports St. John's wort as one of the most popular herbs in the United States. This woody perennial features dark green foliage and yellow blossoms in clusters of three. Cultivators may harvest the entire plant during its flowering stage, but the blossoms contain more active compounds than the rest of the plant, advises the PDR for Herbal Medicines.
Mental and Emotional Effects
St. John's wort contains flavonoids, specifically hypericin, which may induce a feeling of calm and reduce stress levels in adults, the PDR suggests. The ability of this herb to inhibit chemicals in the brain makes it potentially useful in the treatment of mild depression and the hormonal mood swings related to menopause. The Mayo Clinic advises that St. John's may not be effective for long-term treatment of major clinical depression.
Additional mental and emotional conditions that may benefit from St. John's wort include anxiety disorder, premenstrual syndrome (PMS), social phobias and seasonal affective disorder (SAD). Further testing is required to substantiate those claims.
Treatment in Children
Although herbalists may recommend St. John's wort to treat childhood depression or the symptoms of attention deficit hyperactivity disorder (ADHD), the Mayo Clinic warns that scientific research does not back up these claims. Children should only take this herb under medical supervision.
Side Effects
Short-term use of St. John's wort, of up to 3 months in adults, is generally safe, reports the Mayo Clinic, but some side effects may occur in some individuals.
Allergic reactions may include itching and a skin rash. Additional recorded side effects include fatigue, upset stomach, restlessness, impotence, dry mouth and a headache. Discontinue use if you experience thoughts of suicide or homicide and contact your doctor immediately .
Gale reports side effects in breastfeeding mothers who use St. John's wort, which may include milk reduction and reduced nutritional content of breast milk.
Drug Interactions
Taking St. John's wort may cause interactions with current medications, advises Gale. The herb may interfere with the effectiveness of amphetamines, decongestants, traditional depression medications and narcotics. Do not use St. John's wort without your doctor's approval if you're currently taking other medications.
References
- Mayo Clinic: St. John's Wort
- Mayo Clinic: St. John's Wort: Evidence
- Mayo Clinic: Safety of St. John's Wort
- "PDR for Herbal Medicines, 2nd Edition"; Joerg Gruenwald, Ph.D.; 2000
- "Gale Encyclopedia of Alternative Medicine, Volume 4"; Jacqueline L. Longe; 2005
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