St. John's Wort

Hypericum perforatum

Europe's best-evidenced herbal antidepressant — a bright yellow wildflower with a Cochrane-grade track record for mild-to-moderate depression and a serious drug-interaction profile.

At a glance

Fresh flowering tops smell faintly resinous, slightly citrusy, and green. The oil infusion turns a spectacular deep ruby red — a color that once seemed like a magical property. Tea is mildly bitter and astringent.

  • Mild to moderate depression (evidence-based)
  • Menopausal mood swings and irritability
  • Seasonal low mood (winter blues)
  • Topical red oil for nerve pain and wound healing

Modern research

Tradition

St. John's Wort has been the European folk treatment for melancholy, nerve complaints, and wound healing for over 2,000 years. Hung above doors on St. John's Day, its protective role against evil spirits paralleled its therapeutic role in lifting dark moods. The red oil infusion — which turns the color of blood when the fresh flowers steep in oil — was applied to burns, bruises, and nerve pain.

Modern evidence

A 2008 Cochrane review of 29 trials with nearly 5,500 patients found SJW superior to placebo and equivalent to standard antidepressants for mild-to-moderate depression, with significantly fewer side effects. It is not effective for severe depression — a 2002 NIMH-funded trial confirmed no benefit in severe MDD.

The drug interaction problem

Hyperforin strongly induces CYP3A4, the liver enzyme responsible for metabolizing dozens of medications. This can reduce the plasma levels of oral contraceptives (potentially causing contraceptive failure), antiretroviral HIV drugs, cyclosporine (risking organ rejection in transplant patients), warfarin, and many others. Always review your complete medication list before starting SJW.