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Camphor (zhang nao)
What is camphor? What is it used for?
Camphor is a type of evergreen tree native to east Asia. In the wild, they can reach a height of 100 feet, with aromatic, red leaves that turn dark green as they mature; small, yellowish flowers; and oval-shaped red berries. Although the entire tree has medicinal properties, the leaves are of special importance. They are harvested three or four times a year, during which an oil is extracted and distilled to form small, colorless crystals. It is this crystal extract that is used in herbal remedies.
According to the principles of traditional Chinese medicine, camphor has pungent, hot and slightly toxic properties, and is associated with the Heart and Spleen meridians. Traditionally, camphor has been used as a type of insect repellant. Camphor oil is also applied to the skin to treat bruises, sprains, rheumatoid arthritis, and some inflammatory conditions. Camphor fumes may treat asthma, bronchitis, emphysema, and other respiratory disorders. In addition, camphor has several industrial uses, and is often incorporated into soaps, deodorants and disinfectants.
How much camphor should I take?
Because camphor is usually inhaled or applied externally, the amount to be taken depends on the condition being treated. Camphor can ground into a powder and either applied directly to the skin, or mixed with liquid as a wash. Camphor should not be consumed internally.
What forms of camphor are available?
Crystallized camphor may be available at some herbal shops and specialty stores. In addition, some stores sell camphor extracts (which may be inhaled), along with camphor powders and capsules.
What can happen if I take too much camphor? Are there any interactions I should be aware of? What precautions should I take?
Camphor is considered slightly toxic. As a result, it should not be consumed by women who are pregnant or breastfeeding, and should be taken internally only under the supervision of a licensed health care provider. Large doses can irritate the lining of the stomach and cause nausea and vomiting. The American Herbal Products Association has given camphor class 2B and 2D ratings, meaning that it should not be used during pregnancy, and should not be applied to the facial regions of children and infants. The German Commission E recommends camphor for a variety of conditions, but states that it should not be applied to skin that is burned or injured. As always, make sure to consult with a licensed health care provider before taking camphor or any other herbal remedy or dietary supplement.
- Blumenthal M, Busse W, Goldberg A, et al. (eds.) The Complete German Commission E. Monographs. Therapeutic Guide to Herbal Medicines. Boston: Integrative Medicine Communications, 1998, p. 101.
- Chen JK, Chen TT. Chinese Medical Herbology and Pharmacology. City of Industry, CA: Art of Medicine Press, 2004, pp. 1059-1061.
- Gruenwald J, Brendler T, Jaenicke C (eds.) PDR for Herbal Medicines. Montvale, NJ: Medical Economics Company, 2000, pp. 143-144.
- McGuffin M, Hobbs C, Upton R, et al. (eds.) American Herbal Products Association's Botanical Safety Handbook. Boca Raton, FL: CRC Press, 1997, pp. 30-31.
- Miyazawa M, Hashimoto Y, Taniguchi Y, et al. Headspace constituents of the tree remain of cinnamomum camphora. Nat Prod Lett 2001;15(1):63-9.