St. John’s Wort and Depression
St. John’s wort is a plant with yellow flowers that has been used for
centuries for health purposes, such as for depression and anxiety. This
fact sheet answers some frequently asked questions about St. John’s
wort and depression, and summarizes what the science says about its
effectiveness and the research being done.
• Studies suggest that St. John’s wort is of minimal benefit in treating
major depression. A study cofunded by the National Center for
Complementary and Alternative Medicine (NCCAM) found that
St. John’s wort was no more effective than placebo in treating major
depression of moderate severity. There is some scientific evidence
that St. John’s wort is useful for milder forms of depression.
• St. John’s wort interacts with certain drugs, and these interactions
can limit the effectiveness of some prescription medicines.
• St. John’s wort is not a proven therapy for depression. If
depression is not adequately treated, it can become severe and,
in some cases, may be associated with suicide. Consult a health
care provider if you or someone you care about may be
• Tell your health care providers about any complementary and
alternative practices you use. Give them a full picture of what
you do to manage your health. This will help ensure coordinated
and safe care.
About St. John’s Wort
St. John’s wort (Hypericum perforatum) is a long-living plant with
yellow flowers whose medicinal uses were first recorded in ancient
Greece. It contains many chemical compounds. Some are believed to
be the active ingredients that produce the herb’s effects, including
the compounds hypericin and hyperforin.
How these compounds actually work is not yet fully understood, but
several theories have been suggested. Preliminary studies suggest that St.
John’s wort might work by preventing nerve cells in the brain from