St. John’s Wort

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 Overview of Dietary Supplements Dietary supplements are used by about 75% of Americans. They are the most common therapies included among integrative medicine and health (IMH) and complementary and alternative medicine (CAM)... read more .)

People take St. John’s wort mostly to relieve symptoms of mild to moderate depression Depression Depression is a feeling of sadness and/or a decreased interest or pleasure in activities that becomes a disorder when it is intense enough to interfere with functioning. It may follow a recent... read more .

St. John’s wort also has been used in the treatment of skin disorders, including psoriasis Psoriasis Psoriasis is a chronic, recurring disease that causes one or more raised, red patches that have silvery scales and a distinct border between the patch and normal skin. A problem with the immune... read more , and attention-deficit/hyperactivity disorder Attention-Deficit/Hyperactivity Disorder (ADHD) Attention-deficit/hyperactivity disorder (ADHD) is poor or short attention span and/or excessive activity and impulsiveness inappropriate for the child’s age that interferes with functioning... read more (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 drugs that are more effective for HIV infection.

A number of placebo-controlled studies have been done on St. John’s wort. Overall, these studies show St. John’s wort may benefit people with mild to moderate depression and may even be as effective as some traditional antidepressants. However, most studies do not show that St. John's wort is effective for major depression.

The effectiveness of St. John’s wort in treating ADHD or skin disorders has not been well-studied and is considered unproved.

St. John's wort may help relieve menopausal symptoms such as hot flashes.

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.

One of the larger problems with St. John’s wort is that it interacts negatively with a number of drugs people take (see table Drug Interactions With St. John's Wort Some Drug Interactions With St. John's Wort ). These interactions may lead to toxic reactions or ineffectiveness of the drug.

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 drugs 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 drugs for HIV infection should not take St. John’s wort.