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St. John’s Wort


Laura Shane-McWhorter

, PharmD, University of Utah College of Pharmacy

Last full review/revision Jul 2020| Content last modified Jul 2020
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Topic Resources

Medicinal claims

People take St. John’s wort mostly to relieve symptoms of depression Depression A short discussion of prolonged grief disorder. 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... read more . Study results vary, but there may be a benefit in treating mild to moderate short-term depression. Overall, some studies show St. John’s wort may benefit people with mild to moderate depression and may be as effective as some traditional antidepressants. However, St. John's wort is not effective for major depression.

St. John’s wort has been used in the treatment of skin disorders, including psoriasis, and attention-deficit/hyperactivity disorder (ADHD) in children, but its effectiveness in treating these disorders is unproved.

Possible side effects

St. John’s wort may cause increased sensitivity to sunlight. Other side effects include dry mouth, digestive tract symptoms, fatigue, confusion, and mania (in people with bipolar disorder Bipolar Disorder In bipolar disorder (formerly called manic-depressive illness), episodes of depression alternate with episodes of mania or a less severe form of mania called hypomania. Mania is characterized... read more ).

Pregnant women should not take this supplement because it increases muscle tone in the uterus and thus may increase the risk of a miscarriage.

Possible drug interactions

One of the larger problems with St. John’s wort is that it may interact negatively with a number of drugs people take (see table Drug Interactions With St. John's Wort Drug Interactions With St. John's Wort The reddish substance in the plant’s flowers contains numerous biologically active compounds, including hypericin and hyperforin. (See also Overview of Dietary Supplements.) People take St.... read more ). These interactions may lead to toxic reactions or ineffectiveness of the drug.


More Information about St. John’s Wort

The following is an English-language resource that may be useful. Please note that THE MANUAL is not responsible for the content of this resource.

Drugs Mentioned In This Article

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