Advertisement

How does St. John's Wort work?

St. John's wort is an herbal remedy that is sometimes used to treat depression. Many of the psychotropic drugs used to treat depression have side effects which can be severe, and some hope that a natural medicine will cause fewer problems.

Depression is treated in a number of ways, often by the use of anti-depressant drugs, for example Prozac, Paxil, Elavil and Nardil. These can cause side effects such as sleeplessness, headaches, gastrointestinal disturbances and sexual problems. The British Medical Journal reported in 1994 that St. John's wort was about as effective as standard anti-depressants, and worked better than placebos in treating mild to moderate depression.

The active therapeutic ingredients in St. John's wort include hypericin, pseudohypericin and xanthones, and it is believed that other components may support the action of these compounds. Extract preparations of St John's Wort are standardized to 0.3 percent hypericin, so the typical adult dose of 300 milligrams taken three times a day means 2.7 milligrams of hypericin a day.

It is presumed that hypericin helps to affect mood by elevating the biochemicals dopamine and seratonin in the brain. It also reduces adrenal activity, which is increased in depression. However St. John's wort has side effects as well. Light-sensitivity, dry mouth, stomach irritations, dizziness and tiredness can occur.

It is inconclusive whether St. John's wort may help with the treatment of herpes, HIV or leukemia, or if it could help in treating some cancers.

St. John's wort is marketed as a dietary supplement, and so it is not regulated by the U.S. Food and Drug Administration, and taking it should be done under a doctor's supervision.

Continue Learning about St. John's Wort

How should I store St. John's Wort?
Stacy Wiegman, PharmDStacy Wiegman, PharmD
Store St. John's Wort at room temperature. Keep the product in a container that is shut from he...
More Answers
What are the other names for St. John's wort?
Stacy Wiegman, PharmDStacy Wiegman, PharmD
St. John's wort goes by almost 30 other names, the most common being hypericum, Klamath weed and...
More Answers
What questions should I ask my pharmacist about St. John’s wort?
Stacy Wiegman, PharmDStacy Wiegman, PharmD
Ask your pharmacist if St. John's wort may interact with any of the other medications you may be...
More Answers
Who should not use St. John’s Wort?
Stacy Wiegman, PharmDStacy Wiegman, PharmD
You should not use St. John’s Wort if you are allergic to it, if you are using a serotonin reuptake ...
More Answers

Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.