Parts of the plant Thuja occidentalis are a frequent resource in homeopathy, but are rarely used in modern herbal medicine. This is probably due in part to its toxic properties.
T. occidentalis is often referred to by the common names arbor vitae, white cedar, or just Thuja. Thuja is an evergreen conifer of the Cupressaceae family, native to Europe and North America. Its height ranges from 15-20 meters.
Traditional and Modern Use of Thuja
Traditionally, Native Americans used parts of the plant for treating infections and fighting intestinal parasites like hookworms. Modern research substantiates the immune-boosting effects, and alludes to its promise as an adjunct therapy in fighting viral infections.
Effects of Thuja on the human immune system include:
· Protection of cells previously infected by viruses
· The ability to alert white blood cells like T-helper lymphocytes
· Increased production of chemicals used for immune cell communication
· Increased production of antibodies
· Stronger, more powerful macrophages
· Increased immune cell production
Several in vitro and in vivo studies involving cells, animals, and humans substantiate its impact on viral infections. Thuja appears to protect against influenza infection, and keeps alive HIV-infected cells which would normally be killed by the virus.
Many Bioactive Compounds found in Thuja
Many of the immune-stimulating compounds are found in the leaves. These include complex polysaccharides, essential oils, coumarins, and flavonoids. Thujone is a potent ketone monoterpene found in the essential oil. This compound is also associated with the drink absinthe, contributing to its toxicity.
Recommended Dosage for Thuja
Depending on the condition, dosage appears to range between 18-36 mg dried herb for 7-14 days. A safe short term dosage ceiling has been established at 1.25 mg/kg body weight, or 75 mg/day. Avoid if pregnant or breastfeeding.
Toxicity and Adverse Effects Associated with Thuja
Thuja is a powerful toxic herb and should only be used while under the care of an appropriate health care professional. With intoxication due to doses over 75 mg/day for extended periods, consumers may experience severe adverse effects.
Adverse effects related to Thuja intoxication include:
· Vomiting
· Stomach pain
· Headache
· Nervous agitation
· Convulsions
· Liver and renal toxicity
While many herbs have subtle properties, Thuja belongs to a select class with immediate and powerful physiological effects. As a powerful and substantiated immune-stimulating agent it excels. However, due to its toxicity it has fallen out of favor with many practitioners and must be administered only under physician supervision.
Disclaimer: The information contained in this article is for educational purposes only and should not be used for diagnosis or to guide treatment without the opinion of a health professional. Any reader who is concerned about his or her health should contact a doctor for advice.
Additional Resources
Belal Naser et al., “Thuja occidentalis (Arbor vitae): A Review of its Pharmaceutical, Pharmacological and Clinical Properties,” Evidence-based Complementary and Alternative Medicine 2, no. 1 (March 2005): 69-78.
Elizabeth A. Mazzio and Karam F. A. Soliman, “In Vitro Screening of Tumoricidal Properties of International Medicinal Herbs: Part II,” Phytotherapy research : PTR 24, no. 12 (December 2010): 1813-1824.
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