St. John's Wort
by Matt DiFrancesco

Common Names: St. Johns Wort, Hypericum, Klamath Weed, Goatweed

Latin Name: Hypericum perforatum
Binomial Name: Hypericum perforatum
H. perforatum

The medicinal uses for St. John's wort were first recorded in ancient Greece. The name of the plant came from St. John the Baptist because the plants yellow flowers bloom in late June, around the time of the feast of St. John the Baptist. For centuries, St. John's wort has been used to treat nerve pain, and mental disorders, but has also been used as a sedative, and for malaria. St. John's wort has also been used as a balm for wounds, burns, and insect bites. It is used as a folk or traditional remedy for sleep disorders, anxiety, and depression in present day. Teas, tablets, and capsules containing concentrated extracts have been prepared through the use of the flowering tops of St. John's wort. Additionally, liquid extracts and topical preparations have also been used.

Ecology: St. John's wort thrives in an environments that are either winter dominant or summer dominant (rainfall pattern) and reproduces both vegetatively and sexually. Temperatures that are too low to allow for seedling survival and germination may restrict distribution. Limiting thresholds to the flourishing of the plant include; altitudes greater than 1500 meters, rainfall that is less than 500mm, and a daily mean January temperature that is greater than 24 degrees Celsius. St. John's wort may alter growth form and habit depending on environmental and climatic conditions, to allow for survival. In order to grow vegetatively, defoliation by insects or grazing must occur, and also, summer rains must be effective.

It has been found that using St. John's wort may interact with the intended use of medications such as:
  • Antidepressants
  • Birth Control Pills
  • Cyclosporine (revents the body from rejecting transplanted organs)
  • Digoxin (heart medication)
  • Indinavir and possibly other drugs used to control HIV infection
  • Irinotecan and possibly other drugs used to treat cancer
  • Seizure-control drugs, such as phenytoin and phenobarbital

Natural Medicines Comprehensive Database rates effectiveness of St. John's wort based as follows:
Likely effective for...
  • Mild to moderate depression. Taking St. John’s wort extracts improves mood, and decreases anxiety and insomnia related to depression. It seems to be about as effective in treating depression as many prescription drugs. In fact, clinical guidelines from the American College of Physicians-American Society of Internal Medicine suggest that St. John’s wort can be considered an option along with antidepressant medications for short-term treatment of mild depression. However, since St. John’s wort does not appear to be more effective or significantly better tolerated than antidepressant medications, and since St. John’s wort causes many drug interactions, the guidelines suggest it might not be an appropriate choice for many people, particularly those who take other medications. St. John’s wort might not be as effective for more severe cases of depression.
Possibly effective for...
  • Menopausal symptoms. Some research shows that a combination of St. John’s wort plus black cohosh can help improve menopausal symptoms.
  • The conversion of mental experiences or states into bodily symptoms (somatization disorder). Treatment with St. John’s wort seems to reduce symptoms after 6 weeks of treatment.
  • Wound healing. Some research shows that applying a specific St. John’s wort ointment (Gol-Daru Company) three times daily for 16 days improves wound healing and reduces scar formation after a cesarean section.
Possibly ineffective for...
  • Hepatitis C virus (HCV) infection.
  • Irritable bowel syndrome (IBS).
  • Pain conditions related to diabetes (polyneuropathy).
Insufficient evidence to rate effectiveness for...
  • Obsessive compulsive disorder (OCD). There is conflicting evidence about the effectiveness of St. John’s wort for OCD. The reason for contradictory findings could be due to differences in study design, differences in the St. John’s wort products used, or other factors.
  • Premenstrual syndrome (PMS). There is preliminary evidence that St. John’s wort might help reduce PMS symptoms, by even as much as 50% in some women.
  • Seasonal affective disorder (SAD). Early studies suggest that St. John’s wort might help SAD. It appears to improve symptoms of anxiety, decreased sex drive, and sleep disturbances associated with SAD. It is useful alone or in combination with light therapy.
  • Smoking cessation. Research to date suggests that taking a specific St. John’s wort extract (LI-160, Lichtwer Pharma US) 300 mg once or twice daily starting 1 week before and continuing for 3 months after quitting smoking does not improve long-term quit rates.
  • Attention deficit-hyperactivity disorder (ADHD).
  • Stomach upset.
  • Bruises.
  • Skin conditions.
  • Migraine headache.
  • Nerve pain.
  • Sciatica.
  • Excitability.
  • Fibromyalgia.
  • Chronic fatigue syndrome (CFS).
  • Muscle pain.
  • Cancer.
  • Weight loss.
  • Other conditions.

Geographical Distribution:
There are approximately 370 species of the genus Hypericum that exist on our planet. Their native geographical distribution includes both temperate and subtropical regions such as Europe, Turkey, Russia, India, China, Brazil, and even North America. Below you can see the geographical distribution of the species within our country, by the states that are shaded green.
Map_2.png John's wort has been found in all of the states that are shaded green on this map.

Active Ingredients:
St. John's wort contains numerous compounds with documented biological activity. Constituents that have stimulated the most interest include the naphthodianthrones hypericin and pseudohypericin, a broad range of flavonoids, and the phloroglucinols hyperforin and adhyperforin. According to the actual state of scientific knowledge the total extract has to be considered as the active substance. Although there are some open questions, the bulk of data suggests that several groups of active compounds are contributing to the efficacy of the plant extract.

St, John's Wort is marketed as a dietary supplement for calming effects and is mainly targeted for mild to moderate depression. It is advertised as promoting a positive mood and as nutritionally supporting a feeling of well being and normal positive outlook. It is marketed in the form of capsules, tablets, extracts (both solid and liquid), tinctures, ointments, oils, lotions, and tea. St. John's wort is distributed by manufacturers of medical products such as Bayer, Celestial Seasonings, Centrum, Frontier Herbs, Nature's Bounty, and many more.

Ointments made form the plant are marketed as an astringent for bruises, skin irritations, insect bites, and wounds. St John's wort oil is marketed for its therapeutic properties and is used for treatment of abrasions, wounds, and first-degree burns.

St. John's wort. In: Blumenthal M, Goldberg A, Brinckman J, eds.
Herbal Medicine: Expanded Commission E Monographs. Newton, MA: Lippincott Williams & Wilkins; 2000:359–366.
Rapaport MH, Nierenberg AA, Howland R, et al. The treatment of minor depression with St. John's wort or cialopram: Failure to show benefit over placebo. Journal of Psychiatric Research. 2011;45:931–941.

St. John's wort. Natural Medicines Comprehensive Database Web site. Accessed at

St. John's wort (Hypericum perforatum L.). Natural Standard Database Web site. Accessed at

De Smet PA. Herbal Remedies.
New England Journal of Medicine. 2002;347(25):2046–2056.
Hypericum Depression Trial Study Group. Effect of Hypericum perforatum (St. John's wort) in major depressive disorder: a randomized controlled trial. Journal of the American Medical Association. 2002;287(14):1807–1814.