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Other common
name(s): goatweed, amber, klamath weed, tipton weed
Scientific/medical
name(s): Hypericum
perforatum
Description
St. John's wort is a shrub-like perennial herb with bright
yellow flowers that is native to Europe, western Asia, and northern
Africa. Colonists brought it to the United States, where it now grows
widely. The parts of the plant used in herbal remedies are taken from
the flowering tops.
Overview
St. John's wort has been shown to be effective in treating
mild to moderate depression and causes fewer side effects than older
types of antidepressants (tricyclics or TCAs). Data suggest it may be
less effective in treating severe depression. More research is needed
to compare it to newer antidepressants.
St. John's wort is known to interfere with many prescription
drugs, including some used for anesthesia and cancer treatment.
How is it promoted for use?
St. John's wort is widely used in Europe to treat depression,
anxiety, and sleep disorders. In Germany, doctors prescribe it more
often than the popular anti-depressant drug Prozac. Hypericin is the
most commonly studied active ingredient in St. John's wort, and the
amount of this compound is often used to standardize extracts.
The herb is also promoted to treat bronchial inflammation,
bed-wetting, stomach problems, hemorrhoids, hypothyroidism, insomnia,
migraines, kidney disorders, and malaria. A balm made from St. John's
wort can be used on the skin for burns, wounds, insect bites and
stings, and other skin diseases. Although there is some evidence for
using St. John's wort in some emotional conditions besides depression,
available scientific evidence does not support claims that it works for
these other diseases.
What does it involve?
Commission E (Germany's regulatory agency for herbs) has
approved St. John's wort for the treatment of depression and anxiety,
as well as for burns and skin lesions. It is available by prescription
only in Germany. However, it can be purchased in drug stores and health
food stores in the United States as a capsule, tablet, liquid extract,
and as a tea. An average dose is 300 milligrams, taken 3 times a day
for 4 to 6 weeks.
Unfortunately, the potency and purity of different extracts
sold in the United States varies widely. The U.S. Food and Drug
Administration does not regulate herbs as tightly as it does
prescription and over-the-counter medicines and cannot guarantee
strength or purity.
A 2003 study using a new type of test found that most brands
of St. John's wort contained a different amount of hypericin (or
psuedohypericin), one of the active ingredients in St. John's wort,
from what was listed on the label. ranging from 0% to 109% of what was
listed for capsules, and 31% to 80% of what was listed for tablets. On
average, the labels stated that the product contained about twice as
much hypericin and pseudohypericin as it actually contained. Some
products contained no detectable St. John's wort, and others contained
less than a third of what the label stated. Very few contained the
stated amount. This variability can affect the results people might get
when they try to follow a standard dose. Standardized products are
supposed to contain 0.3% hypericin. The variability in strength may
also affect the outcomes of research on the herb, unless researchers
confirm the contents of the brand before testing it.
What is the history behind it?
Use of St. John's wort dates back many centuries and is
surrounded with folklore. Greeks used it to fight fevers and evil
spirits. Its scientific name comes from the Greek words hyper (meaning
over) and eikon (meaning ghost). In pre-Christian rituals in England,
the plant was used to protect a house from evil spirits and to banish
witches. It was thought that a person could be protected from death
during the following year by putting a piece of the plant under a
pillow on St. John's Eve, after which the Saint would appear in a dream
and give his blessing. The plant's common name reflects the fact that
the flowers typically bloom around the birthday of St. John the
Baptist, June 24.
St. John's wort has been used as a folk remedy for centuries
to treat everything from wounds, headaches, gout, and kidney problems
to nervous disorders. After it was brought to this continent, Native
Americans used several species of St. John's wort to treat diarrhea,
wounds, and snakebites.
In the United States, the plant was not well known until after
the 1900s. In 1959, the plant was first studied for its ability to
fight bacteria. Extracts of St. John's wort have become extremely
popular in the United States. Since its interactions with other drugs
have been discovered, there are more concerns about its potential
dangers. Ireland, for instance, banned over-the-counter sales of the
herb in 2000. It is still available by prescription there.
What is the evidence?
Clinical trials have shown that St. John's wort is effective
in treating mild to moderate depression and causes fewer side effects
than older standard antidepressants (tricyclics or TCAs).
Researchers are uncertain about how St. John's wort works to
relieve depression. Hypericin was first recognized as its active
ingredient, but newer information indicates that hyperforin, another
compound in the herb, also plays an important role.
One review that analyzed 23 randomized clinical trials
concluded that St. John's wort was more effective than a placebo, or
inactive substance, for the treatment of mild to moderate depression
and was found to be as effective as standard antidepressants. A more
recent review of controlled, double-blinded studies reached a similar
conclusion. However, the review authors reported that there were
problems with the way the studies were designed and analyzed.
In 2004, a German group analyzed 30 studies that looked at St.
John's wort for mild to moderate depression and found that the herb
compared well to newer antidepressants. In the studies looking at mild
depression, patients taking St. John's wort sometimes had better
results than with standard treatment.
Studies are mixed with regard to its effectiveness in treating
severe depression, but recent clinical trials suggest that it does not
work as well. The U.S. National Institutes of Health—in
cooperation with the Office of Alternative Medicine, the National
Institute of Mental Health, and the Office of Dietary
Supplements—launched a double-blind, controlled clinical
trial using St. John's wort in the treatment of patients with major
depression. A total of 340 adult patients were followed over a period
of 2 to 6 months. The study compared the effects of St. John's wort, a
placebo, and a newer antidepressant called sertraline. The study showed
that neither the St. John's wort nor the sertraline was more effective
than the placebo. This and similar studies suggest that St. John's wort
may not be effective for moderate to severe depression, although this
study was criticized because the approved antidepressant also showed no
benefit.
St. John's wort has also been studied as a treatment for
attention-deficit/hyperactivity disorder. A recent clinical trial for
this condition found St. John's wort to be no different from placebo.
New studies are looking more closely at the interaction of St.
John's wort with birth control pills and strong pain medicines called
opioids. St. John's wort is also being studied to find out whether it
helps in the treatment of minor depression, social phobia, and
obsessive-compulsive disorder.
One nonrandomized clinical trial suggested that St. John's
wort may have potential in helping people to stop smoking. This is an
interesting idea, as other antidepressants have been useful in smoking
cessation. However, additional study is needed before St. John's wort
can be considered to be effective in this situation.
A few laboratory studies are testing some substances from St.
John's wort as a cancer treatment. However, this research is quite
preliminary, and no clinical studies have been reported.
Are there any possible problems or
complications?
This product is sold as a
dietary supplement in the United States. Unlike companies that produce
drugs (which must provide the FDA with results of detailed testing
showing their product is safe and effective before the drug is approved
for sale), the companies that make supplements do not have to show
evidence of safety or health benefits to the FDA before selling their
products. Supplement products without any reliable scientific evidence
of health benefits may still be sold as long as the companies selling
them do not claim the supplements can prevent, treat, or cure any
specific disease. Some such products may not contain the amount of the
herb or substance that is written on the label, and some may include
other substances (contaminants). Though the FDA has written new rules
to improve the quality of manufacturing processes for dietary
supplements and the accurate listing of supplement ingredients, these
rules do not take full effect until 2010. And, the new rules do not
address the safety of supplement ingredients or their effects on health
when proper manufacturing techniques are used.
Most such
supplements have not been tested to find out if they interact with
medicines, foods, or other herbs and supplements. Even though some
reports of interactions and harmful effects may be published, full
studies of interactions and effects are not often available. Because of
these limitations, any information on ill effects and interactions
below should be considered incomplete.
Side effects are not common but include upset stomach,
constipation, fatigue, dry mouth, dizziness, headache, drowsiness,
sleep disturbances, skin rash, and extreme sensitivity to sunlight.
People taking St. John's wort should use sunscreen and eye protection
when exposed to sunlight and should avoid tanning beds. It can also
lower the sex drive. Allergic reactions are rare, but rashes have been
reported. Information on the long-term effects or usage of St. John's
wort is not currently known. In some patients, when the herb has been
taken for more than a month, stopping it suddenly can cause withdrawal
symptoms such as nausea, vomiting, dizziness, dry mouth, and extreme
fatigue.
St. John's wort interferes with several important medicines,
such as HIV drugs (antiretrovirals), blood thinners, birth control
pills, and heart medicines such as digoxin. The herb can reduce the
effectiveness of some anticancer drugs such as irinotecan and imatinib.
It may also interact with drugs such as cyclosporine that keep the body
from rejecting transplanted organs. St. John's wort may increase
sleepiness if used with alcohol, narcotics, sedatives, sleeping
medicines, and anticonvulsants (drugs to prevent seizures). Other
medicines that may interact badly with St. John's wort include an
antidiarrhea medicine called loperamide, an asthma medicine called
theophylline, and some blood pressure medicines.
St. John's wort should not be used with other antidepressants
because it could cause serotonin syndrome. This is a potentially fatal
complication of the brain chemistry involving confusion, fever,
hallucinations, poor coordination, nausea, vomiting, shakiness,
restlessness, sweating, and other symptoms caused by an increase in
serotonin activity.
People taking any prescription medicines or other herbs should
talk to their doctors or pharmacists about possible interactions before
taking St. John's wort. Because of its potential to interfere with
anesthetics, it should be discontinued at least a week before surgery.
People with severe depression or manic depression (bipolar
disorder) should not use St. John's wort. The herb may also increase
muscle contractions of the uterus and is known to pass into breast
milk. It should not be used by pregnant or breast-feeding women.
Relying on this type of treatment alone and avoiding or delaying
conventional medical care for cancer may have serious health
consequences.
Additional Resources
More information from your American Cancer
Society
The following information on complementary and alternative
therapies may also be helpful to you. These materials may be found on
our Web site (www.cancer.org)
or ordered from our toll-free number (1-800-ACS-2345).
References
Barrett S. St. John's wort. Quackwatch Web site.
http://www.quackwatch.org/01QuackeryRelatedTopics/DSH/stjohn.html.
Updated April 16, 2000. Accessed June 6, 2008.
Blumenthal M, ed. The
Complete German Commission E Monographs: Therapeutic Guide to Herbal
Medicines. Austin, TX: American Botanical Council; 1998.
Brennan C. St John's wort - a natural remedy for depression?
Net Doctor.co.uk Web site.
http://www.netdoctor.co.uk/special_reports/depression/stjwort.htm.
Updated January 2, 2000. Accessed June 6, 2008.
Center for Drug Evaluation and Research. Risk of drug
interactions with St. John's wort and Indinavir and other drugs. FDA
Public Health Advisory. US Food and Drug Administration Web site.
http://www.fda.gov/cder/drug/advisory/stjwort.htm.Published February
10, 2000. Accessed June 6, 2008.
Draves AH, Walter SE. Analysis of the hypericin and
peudohypericin content of commercially available St. John's Wort
preparations. Can J
Clin Pharmacol. 2003;10:114-118.
Fetrow CW, Avila JR. Professional's
Handbook of Complementary & Alternative Medicines.
Philadelphia, PA: Lippincott Williams & Wilkins; 2004.
Frye RF, Fitzgerald SM, Lagattuta TF, Hruska MW, Egorin MJ.
Effect of St. John's wort on imatinib mesylate pharmacotherapeutics. Clin Pharmacol Ther.
2004;76:323-329.
Kim HL, Streltzer J, Goebert D. St. John's wort for
depression: a meta-analysis of well-defined clinical trials. J Nerv Ment Dis.
1999;187:532-538.
Lawvere S, Mahoney MC, Cummings KM, Kepner JL, Hyland A,
Lawrence DD, Murphy JM. A Phase II study of St. John's Wort for smoking
cessation. Complement
Ther Med. 2006;14:175-184.
Linde K, Ramirez G, Mulrow CD, Egger M. St John's wort for
depression. Cochrane Database of Syst Rev 2005;(2):CD00448.
Meijerman I, Beijnen JH, Schellens JH. Herb-drug interactions
in oncology: focus on mechanisms of induction. Oncologist.
2006;11:742-752.
National Center for Complementary and Alternative Medicine,
National Institutes of Health. St. John's wort and the Treatment of
Depression. National Center for Complementary and Alternative Medicine
Web site. http://nccam.nih.gov/health/stjohnswort/sjw.pdf. Updated
March 2004. Accessed June 6, 2008.
St. John's wort. Drug Digest Web site.
http://www.drugdigest.org/DD/DVH/HerbsWho/0,3923,4049|St%2E+John%27s+Wort,00.html.
Accessed June 6, 2008.
St. John's wort. Memorial Sloan-Kettering Cancer Center Web
site. http://www.mskcc.org/mskcc/html/69385.cfm. Updated August 6,
2007. Accessed June 6, 2008.
Piscitelli SC, Burstein AH, Chaitt D, Alfaro RM, Falloon J.
Indinavir concentrations and St. John's wort. Lancet.
2000;355:547-548.
Quiney C, Billard C, Salanoubat C, Fourneron JD, Kolb JP.
Hyperforin, a new lead compound against the progression of cancer and
leukemia? Leukemia.
2006;20:1519-1525.
Röder C, Schaefer M, Leucht S. Meta-analysis of
effectiveness and tolerability of treatment of mild to moderate
depression with St. John's Wort [In German] [abstract]. Fortsch Neurol Psychiatr.
2004;72:330-343.
Ruschitzka F, Meier PJ, Turina M, Lüscher TF, Noll G.
Acute heart transplant rejection due to Saint John's wort. Lancet.
2000;355:548-549.
Stavropoulos NE, Kim A, Nseyo UU, Tsimaris I, Chung TD, Miller
TA, Redlak M, Nseyo UO, Skalkos D. Hypericum perforatum L. extract -
novel photosensitizer against human bladder cancer cells. J Photochem Photobiol B.
2006; 84:64-69.
Vorbach EU, Arnoldt KH, Hübner WD. Efficacy and
tolerability of St. John's wort extract LI 160 versus imipramine in
patients with severe depressive episodes according to ICD-10. Pharmacopsychiatry.
1997;30:81-85.
Weber W, Vander Stoep A, McCarty RL, Weiss NS, Biederman J,
McClellan J. Hypericum perforatum (St John's wort) for
attention-deficit/hyperactivity disorder in children and adolescents: a
randomized controlled trial. JAMA.
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Zanoli P. Role of hyperforin in the pharmacological activities
of St. John's wort. CNS
Drug Rev. 2004;10:203-218.
Note: This information may not cover
all possible claims, uses, actions, precautions, side effects or
interactions. It is not intended as medical advice, and should not be
relied upon as a substitute for consultation with your doctor, who is
familiar with your medical situation.
Last Medical Review: 11/01/2008
Last Revised: 11/01/2008
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