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Other common
name(s): eastern white cedar, northern white cedar, yellow
cedar, tree of life, arborvitae, swamp cedar
Scientific/medical
name(s): Thuja
occidentalis
Description
Thuja (pronounced THOO-ya) is an evergreen in the cypress
family, native to eastern North America. The tree is also grown in
Europe as an ornamental plant. The parts used in herbal remedies are
the branches and the tiny, flat, scale-like leaves, which contain the
oil thujone.
Overview
Available scientific evidence does not support claims that
thuja or its extract is safe or effective. Taken internally, the herb
can cause serious side effects, and it may be toxic in large doses. The
essential oil contained in the tree, also known as cedar leaf oil, is
not generally sold for internal use. It is poisonous and can also
irritate or burn skin and eyes.
How is it promoted for use?
Thuja is promoted as a treatment for many medical conditions,
including cancer. Some proponents claim that thuja decreases the toxic
effects of chemotherapy and radiation therapy. Herbalists prescribe
thuja to treat viral and bacterial infections and coughs and other
respiratory ailments, including strep throat and respiratory distress
related to congestive heart failure. Herbalists also use it as a
diuretic to increase urination, and as an astringent to "purify the
blood," reduce inflammation, and cleanse the body of "toxins." Thuja is
sometimes used with antibiotics to treat bacterial skin infections and
herpes sores. It has even been used by some practitioners to induce
abortions. Thuja ointment is applied to the skin for ailments such as
psoriasis, eczema, vaginal infections, warts, muscle aches, and
rheumatism.
Some practitioners of homeopathy (see Homeopathy)
recommend use of very dilute thuja, in pill or liquid form, for
treating irritability, depression, sadness, impaired thinking,
headache, warts, growths, rashes, runny nose, sores in the nose, mouth
pain, toothache, gas, hemorrhoids, watery stool, enlarged prostate,
gonorrhea, back pain, joint pain, bad dreams, tiredness, insomnia,
fevers, shaking chills, muscle pain, and cancer.
What does it involve?
Leaves from the tree are harvested and dried. Liquid extracts,
tinctures, and tea made from thuja are taken internally. There is no
standard dose of the herb. Thuja ointment is applied directly to the
skin. Thuja oil and capsules are available in health food stores and
over the Internet. When properly prepared and dosed as dietary
supplements, the thujone levels are reportedly below the toxic range.
However, because dietary supplements are not considered drugs, the U.S.
Food and Drug Administration (FDA) does not hold them to the same
strict safety requirements that prescription drugs or over-the-counter
drugs must meet.
Homeopathic dilutions of thuja are available to take by mouth,
in pill or liquid form. Thuja is also made into homeopathic creams or
ointments to be applied to the skin. These contain very tiny or even
undectable amounts of thuja.
What is the history behind it?
Native Americans of the eastern United States and Canada used
thuja for generations to treat menstrual problems, headaches, and heart
ailments (see Native American Healing).
Loggers drank tea made from white cedar twigs to relieve rheumatism.
During the seventeenth century, some people called the eastern white
cedar the "tree of life," because they believed that its sap had
healing powers. In the late 1800s, the U.S. Pharmacopoeia (the U.S.
compendium of quality control test and information on drugs) listed
thuja as a treatment to stimulate the uterus and as a diuretic to
increase urine flow.
Thujone (a major component of thuja oil) is banned as a food
or drink additive in the United States, but small amounts are used in
some alcoholic drinks in Europe. It is used in shoe polish and as a
pest repellant. Cedar leaf oil, which is distilled from the leaves of
Thuja occidentalis, is used in some furniture polishes and fragrances.
What is the evidence?
Human clinical trials of thuja by itself have not been
reported. A 2005 German study looked at a mixture of extracts that
included echinacea, baptisia, and thuja in the treatment of 91 adults
with colds and runny noses. Those who received the extracts used fewer
facial tissues than those who got placebo. However, it is impossible to
say how much of this effect was related to thuja.
Available scientific evidence does not support claims that
thuja is effective in treating cancer or any other disease. The medical
literature contains no studies on the effects of thuja as an herbal
remedy in humans, and there is very little scientific data to verify
that the herb has any therapeutic value. Many supporters base their
claims on limited laboratory experiments or individual reports. One
laboratory study done in Germany found that a type of complex sugar
called a polysaccharide from thuja enhanced the immune system's ability
to fight off invading germs. However, even though laboratory studies
may show the substance holds promise, further studies are needed to
find out whether the results apply to humans.
Are there any possible problems or
complications?
This substance
may not have been thoroughly tested to find out how it interacts with
medicines, foods, herbs, or 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.
Because so little is known about thuja, it is not recommended
for any medicinal use. Taken internally, thuja can be toxic in
large doses, although the exact amount that causes problems is
uncertain. Some people who have consumed thuja reportedly experienced
asthma attacks, intestinal irritation, excess stimulation of the
nervous system, and spontaneous abortion (miscarriage).
The essential oil causes spasms if taken internally, and in
high doses it can cause seizures as well as damage to the liver and the
kidneys. The fresh leaves and shoots can also cause poisoning. Deaths
have been reported. Skin or eye contact with cedar leaf oil can cause
severe irritation or burns. Asthma and rashes have occurred in people
who work with the wood of this tree.
Thujone, a component of thuja, is known to cause muscle
spasms, seizures, and hallucinations if taken internally. These
neurological toxicities are the results of thujone interfering with the
action of gamma amino butyric acid, often known as GABA, on nerve cells
in the brain. In high doses thujone is known to damage the liver and
the kidneys. Thujone occurs in a number of other plants, most notably
wormwood and mugwort (see Wormwood
and Mugwort).
People with seizure disorders or gastrointestinal problems
(such as ulcers or gastritis) should avoid thuja. Women who are
pregnant or breast-feeding should not use this herb. 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
Cartier A, Chan H, Malo JL, Pineau L, Tse KS, Chan-Yeung M.
Occupational asthma caused by eastern white cedar (Thuja occidentalis)
with demonstration that plicatic acid is present in this wood dust and
is the causal agent. J
Allergy Clin Immunol. 1986;77:639-645.
Deane PM. Conifer pollen sensitivity in western New York:
cedar pollens. Allergy
Asthma Proc. 2005;26:352-355.
Alpha-thujone (546-80-5). National Toxicology Program Web
site.
http://ntp.niehs.nih.gov/index.cfm?objectid=03DB8C36-E7A1-9889-3BDF8436F2A8C51F.
Updated May 2, 2006. Accessed June 6, 2008.
Fetrow CW, Avila JR. Professional's
Handbook of Complementary & Alternative Medicines.
Philadelphia, PA: Lippincott Williams & Wilkins; 2004.
Gruenwald J. PDR
for Herbal Medicines. 3rd ed. Montvale, NJ: Thomson PDR;
2004.
Material safety data sheet: cedar leaf oil. ScienceLab Web
site. http://www.sciencelab.com/xMSDS-Cedar_leaf_oil-9923339. Updated
October 9, 2005. Accessed June 6, 2008.
Naser B, Lund B, Henneicke-von Zepelin HH, Köhler G,
Lehmacher W, Scaglione F. A randomized, double-blind,
placebo-controlled, clinical dose-response trial of an extract of
Baptisia, Echinacea and Thuja for the treatment of patients with common
cold. Phytomedicine.
2005;12:715-722.
Offergeld R, Reinecker C, Gumz E, Schrum S, Treiber R, Neth
RD, Gohla SH. Mitogenic activity of high molecular polysaccharide
fractions isolated from the cuppressaceae Thuja occidentalis L.
enhanced cytokine-production by thyapolysaccharide, g-fraction (TPSg). Leukemia.
1992;3:189S-191S.
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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