The reddish substance in the flowers of St. John’s wort contains numerous biologically active compounds, including hypericin and hyperforin.
(See also Overview of Dietary Supplements.)
Claims for St. John’s Wort
People take St. John’s wort mostly to relieve symptoms of mild to moderate depression.
St. John’s wort also has been used in the treatment of skin disorders, including psoriasis, and attention-deficit/hyperactivity disorder (ADHD) in children.
There are claims that St. John’s wort can inhibit HIV, the virus that causes AIDS. However, it interferes with the effects of many of the medications that are more effective for HIV infection.
Evidence for St. John’s Wort
The effectiveness of St. John’s wort in treating ADHD or skin disorders has not been well-studied and is considered unproved.
Side Effects of St. John’s Wort
St. John’s wort may increase sensitivity to sunlight. Other side effects include dry mouth, constipation, fatigue, confusion, and, in people with bipolar disorder, mania.
During pregnancy, St. John’s wort increases muscle tone in the uterus and thus may increase the risk of a miscarriage.
Drug Interactions with St. John’s Wort
Recommendations for St. John’s Wort
St. John’s wort may help ease symptoms of anxiety and mild to moderate depression. The American College of Physicians has stated that it may help symptoms of mild to moderate depression and may cause fewer side effects than conventional antidepressants.
However, St. John’s wort interacts negatively with many medications people take, so they should check with their doctor before taking it. Some countries have banned its use due to the numerous drug interactions.
Pregnant women and people taking medications for HIV infection should not take St. John’s wort.
More Information
The following English-language resource may be useful. Please note that THE MANUAL is not responsible for the content of this resource.
National Institutes of Health's National Center for Complementary and Integrative Health: St. John’s Wort
