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St. John's
Wort
Prepared by Susan A. Latta
What are the folklore uses of
St. John's wort?
St. John's Wort has been used in the
past as a blood purifier, in easing tumors and boils, in chronic uterine
problems, and to correct irregular menstruation. None of these uses is
appropriate for St. John's Wort.
What is St. John's wort?
The herb produces golden yellow flowers
which, with the leaves, appear to have a medicinal effect.
What are its proposed
medicinal uses?
It is primarily used as an
antidepressant. It also has been used to reduce diarrhea, pain, and high
fever. It can be a diuretic, and has been used in the treatment of conditions
ranging from insomnia to gastritis. St. John's Wort also is applied externally
to relieve inflammation, promote healing, and as a treatment for hemorrhoids.
How effective is St. John's
wort?
In Germany, it is prescribed as a
treatment for mild and moderate depression, anxiety, and nervousness. A large
trial experiment is being planned to identify effectiveness, detect side
effects, and assess long-term results. It appears more effective for those who
are mildly or moderately depressed. Its use is discouraged for individuals
with severe depression.
How does St. John's wort
appear to work as an antidepressant?
Serotonin, a neurotransmitter in the
brain, acts to elevate a person's mood. Depression sets in when there is not
enough serotonin. While the way in which St. John's Wort works is not clearly
understood, its active compound, hypericin, appears to maintain adequate
levels of serotonin and mood-boosting norepinephrine by blocking the action of
the MOA (monoamine oxidase) enzyme. Overactivity of the MOA enzyme can result
in depression.
What are the side effects of
St. John's wort?
Research suggests that it has fewer side
effects than other antidepressant medications. Although as few as 1 percent of
users have reported side effects, their symptoms include gastrointestinal
disturbances, allergic reactions, and fatigue. Hypericin is known to induce
sensitivity to the sun. Because St. John's Wort's effects are similar to those
of an MAO inhibitor, it may have some additional side effects. There is a risk
of hypertension if it is taken with food that contains the natural chemical
tyramine, found in beer on tap, red wine, liquors, aged meat and cheese, yeast
extract, and soy sauces. Check with a physician before using St. John's Wort,
especially if you take medication for hypertension.
What precautions should be
considered?
St. John's Wort is not necessarily a
better or safer way to treat depression. Over-the-counter remedies for
depression may encourage self-diagnosis, which can be harmful; other
conditions can appear to be depression. While there have been no deaths
reported from an overdose of St. John's Wort, there have been documented cases
of fatal overdoses of antidepressants.
Sources:
Tyler, V. 1993. The Honest Herbal. The
Haworth Press, Binghamton, N.Y. 3rd
edition. pp. 275-276.
An Herb to Alleviate Depression: Weighing
in on St. John’s Wort, Tufts
University Health and Nutrition
Letter, January 1998. p. 8.
A Natural Remedy for Depression? Johns
Hopkins Medical Letter, Health After 50,
October 1997. pp. 2-3.
Kansas State University
The information in this
fact sheet is for educational purposes only and is not meant as a substitute for
advice from your health care physician.
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