Background

• Cedar leaf oil comes from the Thuja occidentalis tree. It has been used historically by different cultures to treat many conditions, including breathing disorders, cancers, headaches, heart ailments, infections, inflammatory disorders, menstrual problems, and urinary disorders. Furthermore, Thuja has been used to induce abortions.
• Thuja is closely related to other cedar genera also used as dietary supplements, including as Cedrus (common name: cedar) and Juniperus (common name: juniper).
• Very little scientific evidence exists regarding Thuja. Clinical trials evaluating Thuja alone are lacking, and the available data are questionable.
• Preclinical studies have demonstrated anticancer and immune-stimulating properties, but further research is necessary. Thuja is often used in homeopathy as a remedy for skin, urinary, and reproductive organ complaints. The herb is also used in combination with Echinacea purpurea, Echinacea pallida, and Baptisia tinctoria to relieve symptoms of common cold and upper respiratory tract infections and as supportive therapy to standard antibiotics.

References

1. Cartier A, Chan H, Malo JL, Pineau L, Tse KS, and 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(4):639-645. View Abstract
2. Deane PM. Conifer pollen sensitivity in western New York: cedar pollens. Allergy Asthma Proc 2005;26(5):352-355. View Abstract
3. Elsasser-Beile U, Willenbacher W, Bartsch HH, Gallati H, Schulte Monting J, and von Kleist S. Cytokine production in leukocyte cultures during therapy with Echinacea extract. J Clin Lab Anal. 1996;10(6):441-445. View Abstract
4. Gohla SH, Haubeck HD, Schrum S, Soltau H, and Neth RD. Activation of CD4-positive T cells by polysaccharide fractions isolated from the Cupressaceae Thuja occidentalis L. (Arborvitae). Haematol.Blood Transfus. 1989;32:268-272. View Abstract
5. Hauke W, Kohler G, Henneicke-von Zepelin HH, and Freudenstein J. Esberitox N as supportive therapy when providing standard antibiotic treatment in subjects with a severe bacterial infection (acute exacerbation of chronic bronchitis). A multicentric, prospective, double-blind, placebo-controlled study. Chemotherapy 2002;48(5):259-266. View Abstract
6. Henneicke-von Zepelin H, Hentschel C, Schnitker J, Kohnen R, Kohler G, and Wustenberg P. Efficacy and safety of a fixed combination phytomedicine in the treatment of the common cold (acute viral respiratory tract infection): results of a randomised, double blind, placebo controlled, multicentre study. Curr Med Res Opin. 1999;15(3):214-227. View Abstract
7. MacLaughlin BW, Gutsmuths B, Pretner E, Jonas WB, Ives J, Kulawardane DV, and Amri H. Effects of homeopathic preparations on human prostate cancer growth in cellular and animal models. Integr.Cancer Ther 2006;5(4):362-372. View Abstract
8. Millet Y, Jouglard J, Steinmetz MD, Tognetti P, Joanny P, and Arditti J. Toxicity of some essential plant oils. Clinical and experimental study. Clin Toxicol. 1981;18(12):1485-1498. View Abstract
9. Naser B, Bodinet C, Tegtmeier M, and Lindequist U. Thuja occidentalis (Arbor vitae): A Review of its Pharmaceutical, Pharmacological and Clinical Properties. Evid.Based Complement Alternat.Med 2005;2(1):69-78. View Abstract
10. Naser B, Lund B, Henneicke-von Zepelin HH, Kohler G, Lehmacher W, and 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(10):715-722. View Abstract
11. Offergeld R, Reinecker C, Gumz E, Schrum S, Treiber R, Neth RD, and 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;6 Suppl 3:189S-191S. View Abstract
12. Ramsewak RS, Nair MG, Stommel M, and Selanders L. In vitro antagonistic activity of monoterpenes and their mixtures against 'toe nail fungus' pathogens. Phytother.Res 2003;17(4):376-379. View Abstract
13. Singh SK, Shanmugavel M, Kampasi H, Singh R, Mondhe DM, Rao JM, Adwankar MK, Saxena AK, and Qazi GN. Chemically standardized isolates from Cedrus deodara stem wood having anticancer activity. Planta Med 2007;73(6):519-526. View Abstract
14. Sunila ES, Kuttan G. A preliminary study on antimetastatic activity of Thuja occidentalis L. in mice model. Immunopharmacol.Immunotoxicol. 2006;28(2):269-280. View Abstract
15. Thangapazham RL, Gaddipati JP, Rajeshkumar NV, Sharma A, Singh AK, Ives JA, Maheshwari RK, and Jonas WB. Homeopathic medicines do not alter growth and gene expression in prostate and breast cancer cells in vitro. Integr.Cancer Ther 2006;5(4):356-361. View Abstract