St. John's Wort for Treating Depression

Medically Reviewed by Smitha Bhandari, MD on July 17, 2023
Written by Debra Fulghum Bruce, PhD
3 min read

Millions of people have tried St. John's wort, an herbal remedy, as an alternative or natural treatment for depression. Is it effective?

The FDA says dietary supplements include herbs like St John's wort, vitamins, minerals, and amino acids. They come in pills, liquids, and powders, and are intended to supplement your diet. They aren't regulated the same way as medications are.

The St. John's wort plant has yellow flowers and is a weed in some parts of the U.S. It has been used for medicinal purposes in other parts of the world for thousands of years. Many studies have evaluated the effectiveness of St. John's wort. Some studies have shown a benefit, but other studies have not.

If you choose to use it, be sure to learn all you can about it, and check with your doctor before taking it. St. John's wort can interact with medicines or supplements you may be taking and may have side effects.

There is some scientific evidence that St. John's wort may help treat mild depression, and the benefit seems similar to that of antidepressants. But two large studies, one sponsored by the National Center for Complementary and Alternative Medicine (NCCAM), showed that the herb wasn't more effective than a placebo in treating moderately severe major depression. The conventional drugs also studied didn't fare any better than a placebo, either.

St. John's wort is most often taken in liquid or capsules. The dried herb may also be used as a tea.

The most common dose used in studies has been 300 milligrams, three times a day as a standardized extract. Preparations in the U.S. have varied amounts in them. So be careful to note how much you're getting.

You should be alert for any of the following effects:

  • Allergic reactions
  • Fatigue and restlessness
  • Increased blood pressure
  • Increased sensitivity to the sun, especially if you are fair-skinned and take large doses
  • Upset stomach

Don't combine St John's wort and prescription antidepressants such as SSRIs. That can cause a problem of too much serotonin, called serotonin syndrome.  You may have to wait a period of time before you start St. John's wort even if you and your doctor decide to stop taking an antidepressant. (Don't stop taking an antidepressant on your own.)

Avoid foods or drinks that contain a chemical called tyramine. These items include aged cheeses, cured meats, sauerkraut, soy sauce, miso, tofu, beer, and wine. Some research shows that when St. John's wort mixes with tyramine, it can lead to serious problems including high blood pressure, fast heart rate, and becoming delirious.

Herbal remedies aren't recommended for pregnant women, children, the elderly, or people with certain medical conditions or taking certain medicines.

Research from the National Institutes of Health shows that St. John's wort may reduce the effectiveness of several drugs, including birth control pills, drugs used to prevent organ transplant rejections, and some heart disease medications. Talk to your doctor about all the medications you take.

If you have side effects such as nausea, vomiting, rapid heartbeat, anxiety, insomnia, diarrhea, or skin rashes, stop taking St. John's wort and tell your doctor.

Beware of commercial claims of what St. John's wort can do. Look for scientific-based sources of information.

Only buy products that list the herb's common and scientific name, the name and address of the manufacturer, a batch and lot number, expiration date, dosage guidelines, and potential side effects.