St. John's Wort and Depression
St. John's wort is a plant with yellow flowers that has been used
for centuries for depression and anxiety health purposes, such as
for . This fact sheet answers some frequently asked questions about St. John's
wort and depression, and summarizes what the science says about its effectiveness and the research
- Studies suggest that St. John's wort is of minimal benefit in treating major depression. A study cofunded
by the National Center for Complementary and Alternative Medicine (NCCAM) found that St. John's wort was no
more effective than placebo in treating major depression of moderate severity. There is some scientific
evidence that St. John's wort is useful for milder forms of depression.
- St. John's wort interacts with certain drugs, and these interactions can limit the effectiveness of some
- St. John's wort is not a proven therapy for depression. If depression is not adequately treated, it can
become severe and, in some cases, may be associated with suicide. Consult a health care provider if you or
someone you care about may be experiencing depression.
- Tell your health care providers about any complementary and alternative practices you use. Give them a full
picture of what you do to manage your health. This will help ensure coordinated and safe care.
About St. John's Wort
St. John's wort (Hypericum perforatum) is a long-living plant with yellow flowers whose medicinal
uses were first recorded in ancient Greece. It contains many chemical compounds. Some are believed to be the active
ingredients that produce the herb's effects, including the compounds hypericin and hyperforin.
How these compounds actually work is not yet fully understood, but several theories have been suggested.
Preliminary studies suggest that St. John's wort might work by preventing nerve cells in the brain from reabsorbing
the chemical messenger serotonin, or by reducing levels of a protein involved in the body's immune system
St. John's wort has been used over the centuries for mental conditions, nerve pain, and a wide variety of other
health conditions. Today, St. John's wort is used for anxiety, mild to moderate depression, and sleep
In Europe, St. John's wort is widely prescribed for depression. In the United States, there is public interest in
St. John's wort as a treatment for depression, but it is not a prescription medicine.
In the United States, St. John's wort products are sold as:
- Capsules and tablets
- Teas—the dried herb. A plant or part of a plant used for its flavor, scent, or potential therapeutic
properties. Includes flowers, leaves, bark, fruit, seeds, stems, and roots. is added to boiling water and
- Liquid extracts—specific types of chemicals are removed from the herb, leaving the desired chemicals in a
Depression is a medical condition that affects nearly 21 million American adults each year, according to the
National Institute of Mental Health. Mood, thoughts, physical health, and behavior all may be affected. Symptoms of
depression commonly include:
- Persistent sad, anxious, or "empty" feelings
- Feelings of hopelessness and/or pessimism
- Feelings of guilt, worthlessness, and/or helplessness
- Restlessness or irritability
- Loss of interest or pleasure in activities that the person once enjoyed
- Fatigue and decreased energy
- Difficulty concentrating, remembering details, and/or making decisions
- Insomnia, early–morning wakefulness, or excessive sleeping
- Overeating, or appetite loss
- Thoughts of suicide, suicide attempts
- Persistent aches or pains, headaches, cramps, or digestive problems that do not ease with treatment.
Depression comes in several forms and its symptoms and severity can vary from person to person. For example:
- In major depression (also called major depressive disorder), people experience
symptoms that interfere with their ability to work, study, sleep, eat, and take pleasure in activities they
once enjoyed. Symptoms last for at least 2 weeks but frequently last for several months or longer.
- In dysthymia (also called dysthymic disorder), a less severe, but more chronic form of
depression, people experience symptoms that are not as disabling but keep them from functioning well or feeling
good. Symptoms last at least 2 years. Many people with dysthymia also have episodes of major depression.
- In bipolar disorder (also called manic–depressive illness), people have periods of
depressive symptoms that alternate or may co-exist with periods of mania. Symptoms of mania include abnormally
high levels of excitement and energy, racing thoughts, and behavior that is impulsive and inappropriate.
In addition, milder forms of depression exist that fall into the category of minor depression. In minor
depression, people experience the same symptoms as major depression, but they are fewer in number and are
less disabling. Symptoms last at least 6 months but less than 2 years continuously.
Depression can be treated effectively with conventional medicineMedicine as practiced by holders of M.D. (medical
doctor) or D.O. (doctor of osteopathy) degrees and by their allied health professionals such as physical
therapists, psychologists, and registered nurses., including antidepressants and certain types of
What the Science Says About St. John's Wort for Depression
Scientific evidence regarding the effectiveness of St. John's wort for depression is inconsistent. An analysis of
the results of 37 clinical trials concluded that St. John's wort may have only minimal beneficial effects on major
depression. However, the analysis also found that St. John's wort may benefit people with minor depression; these
benefits may be similar to those from standard antidepressants. Overall, St. John's wort appeared to produce fewer
side effects than some standard antidepressants.
One of the studies included in the analysis was cofunded by NCCAM and two other components of the National
Institutes of Health (NIH)—the National Institute of Mental Health and the Office of Dietary Supplements. This
study found that St. John's wort was no more effective than placebo in treating major depression of moderate
severity. However, the antidepressant sertraline, used in one arm of the study, also showed little difference from
Side Effects and Risks
The most common side effects of St. John's wort include dry mouth, dizziness, diarrhea, nausea, increased
sensitivity to sunlight, and fatigue.
Research has shown that taking St. John's wort can limit the effectiveness of some prescription medicines,
- Antidepressant medicines
- Birth control pills
- Cyclosporine, a medicine that helps prevent the body from rejecting transplanted organs
- Digoxin, a medicine used to strengthen heart muscle contractions
- Indinavir and other medicines used to control HIV infection
- Irinotecan and other anticancer medicines
- Warfarin and related medicines used to thin the blood (known as anticoagulants)
When combined with certain antidepressants, St. John's wort also may increase side effects such as nausea,
anxiety, headache, and confusion.
Herbal Products: Issues To Consider
Herbal products such as St. John's wort are classified as dietary supplements by the U.S. Food and Drug
Administration (FDA). The FDA's requirements for testing and obtaining approval to sell dietary supplements are
different from its requirements for drugs. Unlike drugs, herbal products can be sold without requiring studies on
dosage, safety, or effectiveness.
The strength and quality of herbal products are often unpredictable. Products can differ in content not only from
brand to brand, but from batch to batch. Information on labels may be misleading or inaccurate.
In addition, "natural" does not necessarily mean "safe." Many natural substances can have harmful
effects–especially if they are taken in large quantities or if they interact with other supplements or with
Tell your health care providers about any complementary and alternative practices you use. Give them a full picture
of what you do to manage your health. This will help ensure coordinated and safe care.
NCCAM Research on St. John's Wort
Recent projects supported by NCCAM include studies of the:
- Safety and effectiveness of St. John's wort for the treatment of minor depression
- Safety of St. John's wort for the treatment of social anxiety disorder
- Effectiveness of St. John's wort for the treatment of obsessive–compulsive disorder
- Effects of St. John's wort on how well birth control pills work
- Possible adverse interactions of St. John's wort and narcotic pain medicines
- Safety and effectiveness of St. John's wort for attention deficit hyperactivity disorder