How St. John's Wort interacts with Drugs metabolized by the cytochrome P-450 pathway

Interaction type: Interactions

Interaction rating: Potential/Theoritical

Studies have reported that St. John's wort may alter the metabolism or breakdown of certain medications in the body which may change the effects of these medications and possibly the dose needed for treatment. Use with caution. (1) (2)


  1. View Abstract: Piscitelli SC, et al. Indinavir Concentrations and St. John's Wort. Lancet. Feb2000;355(9203):547-48.
  2. View Abstract: Markowitz JS, Donovan JL, DeVane CL, et al. Effect of St. John's Wort on drug metabolism by induction of cytochrome p450 3A4 enzyme. Obstet Gynecol Surv. May2004;59(5):358-9.