St. John's Wort

Even if you're an herbal novice, chances are you've stumbled across St. John's Wort in the media or on your drug store shelf. In fact, St. John's Wort, derived from a yellow flowering plant, has been used as an herbal remedy for mild to moderate depression, anxiety, and sleep disturbances/disorders for many years, especially in Germany, where this herb is a prescribed more frequently than most antidepressant medications. What's more, St. John's Wort is one of the most researched herbs around.

How It Works

For a while, experts believed the substance hypericin was the active ingredient in St. John's Wort. However, evidence is lacking that hypericin itself is an antidepressant. Instead, more recent research has focused on another component of St. John's Wort as the potential active ingredient - hyperforin. Some studies suggest that hyperforin may raise levels of serotonin, norepinephrine, and dopamine - neurotransmitters that help lift spirits and boost mood. Nonetheless, there may be other ingredients in St. John's Wort also at work. A handful of double-blind trials using a form of St. John's Wort with low hyperforin content found the herb just as effective in combating mild cases of depression.

What It Might Do for You

St. John's Wort should never be relied on for the treatment of severe depression. If you or someone you know are feeling suicidal, anxious, irritable or have experienced a change in appetite and/or sleep patterns, see your health care provider immediately as drug treatment may be more appropriate for you.

Potential Side Effects

With heavy use, St. John's Wort may increase sensitivity to sunlight. To avoid sunburn, minimize your exposure to the sun while using this medication.

Herb-Drug Interactions

The biggest concern with St. John's Wort is the possibility that it may decrease the effectiveness of various medications, including protease inhibitors (Agenerase, Crixivan, Viracept, Norvir, Fortovase, Invirase), Cyclosporine, Digoxin, Coumadin, chemotherapy drugs, oral contraceptives, Olanzapine or Clozapine, and Theophylline.

St. John's Wort is particularly dangerous if you are taking protease inhibitors for HIV - especially Crixivan. In a study of healthy volunteers, St. John's Wort was found to decrease the blood concentration of Crixivan by 49% to 99%. St. John's Wort may also reduce the effectiveness of other protease inhibitors. All of this could lead to drug resistance, thereby creating resistant strains of HIV.

Furthermore, if you are taking St. John's Wort and any of the above-mentioned medications at the same time and abruptly stop taking the herb, blood levels of the drug may rise. Such a rise may be lethal in certain cases. Be sure to talk to your health care provider to see if St. John's Wort is right for you.

Principal Author:

Stefanie Perelman, M.S., R.D., holds a B.A. in journalism from the University of Wisconsin-Madison and a master's in clinical dietetics from New York University. A registered dietitian, she presently works at Montefiore Medical Center in the Bronx and is available for private consultation.

Nutrition Editor:

Donna Tinnerello MS, RD, CD/N is registered dietitian with more than 10 years experience in HIV and nutrition. She works in lower Manhattan at Cabrini Medical Center, the community and in private practice. Her subspecialties are cardiovascular, renal, gastrointestinal disease, diabetes and weight loss. Donna is available for private consultation by referral only.