If you surf the web or read your local newspaper, you've probably seen something about herbal supplements, such as St. John’s wort, and their role in treating depression. Although dozens of people swear by it, St. John's wort is still considered an alternative therapy by many experts.

St. John's Wart | Cleveland Clinic

St. John's Wort

A wild yellow flower regarded as a weed throughout most of the United States, St. John's wort has been used for medical purposes in other parts of the world for thousands of years. Named for St. John the Baptist (because it blooms around the day of his feast), St. John's wort is continually being studied to try to demonstrate its alleged benefits.

According to several of these studies, St. John’s wort may be more effective than a placebo (sugar pill), and as effective as prescription antidepressants, in treating mild depression. Two studies in the United States found that St. John’s wort was no better than a placebo for treating moderate to severe depression.

The true benefits of St. John's wort are still being explored. If you do choose to use it, however, here is some information you'll need to know.

How do I take St. John's wort?

Preparations in the U.S. have different amounts of active ingredient, so be careful to note how much you're getting in your tablets. Depending on the preparation, St. John’s wort can be taken in any of the following ways:

  • 300 mg three times a day for up to six weeks;
  • 250 mg twice a day for six weeks;
  • 300 to 600 mg three times a day for six weeks;
  • 350 mg three times a day for eight weeks;
  • 300 to 600 mg three times a day for up to 26 weeks;
  • 400 mg twice a day for six weeks.

What are the potential benefits of using St. John's wort?

  • Reduction in symptoms of depression
  • Reduction in menopausal symptoms
  • Assistance with wound healing (when applied to the skin as a lotion)

What should I watch out for if I use St. John's wort?

  • Increased sensitivity to the sun, especially if you are fair-skinned and taking large doses
  • Increase in blood pressure

Do not take St. John's wort during pregnancy or while you are breastfeeding.

St. John’s wort has been associated with very serious and potentially dangerous interactions with many common drugs. St. John’s wort can weaken how well other drugs work, including antidepressants, birth control pills, cyclosporine (an anti-rejection drug), digoxin (a heart drug), HIV drugs, cancer medications, and blood thinners such as Coumadin.

Taking St. John’s wort with antidepressants can cause a dangerous increase in levels of serotonin, a hormone that affects mood. This condition is known as serotonin syndrome.

Always tell your doctor or pharmacist if you are taking St. John's wort or any other herbal product. St. John’s wort should not be used in place of standard antidepressants.

Last reviewed by a Cleveland Clinic medical professional on 05/16/2017.

Cleveland Clinic is a non-profit academic medical center. Advertising on our site helps support our mission. We do not endorse non-Cleveland Clinic products or services. Policy