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St. John’s Wort

For centuries, the flowering plant St. John's wort was used as a health remedy in Europe. Today, St. John's wort is best-known as a treatment for depression.

St. John's Wort Uses

Some studies have found St. John's wort helpful for depression. In fact, a few showed that St. John's wort was as effective as some prescription antidepressants. But the evidence is conflicting. Two recent major studies showed that St. John's wort worked no better than a placebo for moderate depression. St. John's wort might prove more effective for milder forms of depression. For now, however, the evidence is uncertain.

St. John's wort has also been studied in the treatment of other mood disorders, such as severe depression, anxiety disorders, obsessive compulsive disorder (OCD), and seasonal affective disorder (SAD.) It's also been used for insomnia, PMS, menopausal symptoms, and eczema. However, studies on St. John's wort for these uses have not shown solid evidence of benefit.

St. John's Wort Dose and Instructions for Use

For depression, the standard dose for adults is 300 milligrams of St. John's wort (of 0.3% hypericin extract) taken three times a day. After the initial treatment, some people choose to go onto a lower maintenance dose of 300 milligrams to 600 milligrams of St. John's wort per day.

St. John's Wort Food Sources

There are no natural food sources of St. John's wort.

St. John's Wort Supplement Information

St. John's wort may be sold as capsules, tablets, teas, and liquid extracts. In general, most St. John's wort is standardized to 0.3% hypericin extract. Switching between products with higher and lower percentages of an extract may not be a good idea. Like any supplement, keep St. John's wort supplements in a cool, dry place, away from humidity and direct sunlight.

St. John's Wort Warnings

• Side effects. At recommended doses, St. John's wort generally does not cause side effects. Uncommon side effects of St. John's wort include anxiety, dry mouth, sensitivity to sunlight, dizziness, stomach upset, headache, sexual problems, and fatigue.
• Risks. Depression is a serious and potentially life-threatening disease. Never try to treat it on your own without the help of an expert. Given the lack of evidence about its safety, St. John's wort is not recommended for children or for women who are pregnant or breastfeeding.
• Interactions. You should not take St. John's wort if you're using antidepressants, birth control pills, blood thinners, medicines for HIV, cancer drugs, cyclosporine, or digoxin. St. John's wort may interfere with how these drugs work.