Written by Katja Boehm and the CAM-Cancer Consortium.
Updated February 8, 2017

Essiac

Is it safe?

There is no literature regarding the safety of Essiac. The above review from the Natural Standard Collaboration notes that there is a lack of safety data for Essiac and the other preparations that are marketed under the exact formula12. However, it cannot be assumed that Essiac is safe as it is a product with an unknown safety profile particularly with regards to use during pregnancy and lactation and concomitant use with other drugs.

Patients are also at risk as they are advised that no other treatment, including chemotherapy and radiotherapy, should be used while taking Essiac.

Adverse effects associated with its use have not been reported. The constituent herbs may cause allergic dermatitis and have a laxative effect29,30.

Contraindications

None currently known

Precautions/warnings

None currently known.

Adverse effects and interactions

The following information regarding safety, adverse effects and interactions is available from Natural Medicines Comprehensive Database 31 for the individual plants Essiac contains:

Burdock root (Arctium lappa L.) Orally, burdock can cause an allergic reaction. Rarely, it has caused anaphylaxis32. Theoretically, taking burdock with anticoagulant or antiplatelet drugs might increase the risk of bleeding due to decreased platelet aggregation.
Indian rhubarb root (Rheum palmatum) Orally, rhubarb can cause cramp-like or spasmodic gastrointestinal discomfort, watery diarrhoea, and uterine contractions; there is also one report of anaphylaxis with short-term use33. Chronic use or abuse of rhubarb can cause electrolyte loss (especially potassium), hyperaldosteronism, accelerated bone deterioration, albuminuria, hematuria, dehydration, inhibition of gastric motility, pseudomelanosis coli (pigment spots in intestinal mucosa), arrhythmias, muscular weakness, nephropathies, and edema34.

Sorrel (Rumex acetosa L.). Orally, excessive amounts of sorrel can cause diarrhoea, nausea, polyuria, dermatitis and gastrointestinal symptoms. Theoretically, concomitant oral administration may cause precipitation of some drugs due to the high tannin content of sorrel.35.

Slippery elm bark (Ulmus rubra Muhl.) Orally, the whole bark is an abortifacient36. Topically, slippery elm extracts can cause contact dermatitis and the pollen is an allergen. In theory, the consumption of slippery elm bark when taken with other drugs may slow the absorption and reduce serum levels of orally administered drugs due to mucilage content35.

Watercress (Nasturtium officinale). Orally, large amounts of watercress can cause gastrointestinal irritation33. Theoretically, excessive or prolonged use might cause kidney damage35. Consuming large amounts of watercress with high vitamin K content might theoretically antagonize the anticoagulant effects of warfarin37.

Blessed thistle (Centaurea = Cnicus benedictus). When administered orally and used in doses greater than 5g/cup of tea, it can cause stomach irritation and vomiting34.

Red clover (Trifolium pratense). The oral administration can cause rash-like reactions, myalgia, headache, nausea, and vaginal spotting38. Concomitant use with drugs that have constituents that might affect platelet aggregation could theoretically increase the risk of bleeding in some people. Concomitant use of large amounts of red clover can theoretically increase the anticoagulant effects and bleeding risk of these drugs due to its coumarin content37. There is some concern that red clover might interfere with the effects of tamoxifen because of its potential estrogenic effects38.

Kelp (Laminaria digitata). Orally, kelp can induce or exacerbate hyperthyroidism39,40. The iodine in kelp can cause idiosyncratic reactions. Prolonged high intake of dietary iodine is associated with goitre and an increased risk of thyroid cancer41. Kelp seems to have anticoagulant effects and therefore, theoretically, taking kelp with antiplatelet or anticoagulant drugs might increase the risk of bruising and bleeding42.

Quality issues

The quality of the mixture depends on the quality of each individual ingredient used in preparing the mixture.

Citation

Katja Boehm, CAM-Cancer Consortium. Essiac [online document]. http://cam-cancer.org/The-Summaries/Herbal-products/Essiac. February 8, 2017.

Document history

Assessed as up to date in February 2017 by Barbara Wider.
Assessed as up to date in April 2016 by Barbara Wider.
Assessed as up to date in January 2015 by Barbara Wider.
Assessed as up to date in February 2013 by Katja Boehm.
Fully revised and updated in December 2011 by Katja Boehm.
Fully revised and updated in August 2009 by Katja Boehm.
Summary first published in May 2005, authored by Katja Boehm and Edzard Ernst.

References

  1. Kaegi E. Unconventional therapies for cancer: 1. Essiac. The Task Force on Alternative Therapies of the Canadian Breast Cancer Research Initiative. CMAJ 1998;158:897-902.
  2. Boon H, Wong J. Botanical medicine and cancer: a review of the safety and efficacy. Expert Opin Pharmacother 2004;5:2485-501.
  3. Tai J, Cheung S, Wong S, Lowe C. In vitro comparison of Essiac and Flor-Essence on human tumor cell lines. Oncol Rep 2004;11:471-6.
  4. Thomas R. The Essiac report: The True Story of a Canadian Herbal Cancer Remedy and of the Thousands of Lives it Continues to Save, 3rd ed. Los Angeles: Alternative Treatment Information Networks, 1993.
  5. Meehan D, Agar J. Doctor’s license suspended; some patients still support him. The Grand Rapids Press, April 18th, 1997:12.
  6. NIH National Cancer Institute. Essiac/Flor Essence PDQ. [Online documents]. Available at: https://www.cancer.gov/about-cancer/treatment/cam/hp/essiac-pdq#cit/section_3.4, accessed 8 February 2017. 
  7. Henderson IWD. Director, Bureau of Human Prescription Drugs, Health Protection Branch, Health and Welfare Canada, Vanier, Ontario. Letter to J.W. Meakin. Executive Director, Ontario Cancer Treatment and Research Foundation, Toronto, Ontario, November 19th 1982.
  8. Boon H. Use of complementary / alternative medicine by breast cancer survivors in Ontario: Prevalence and perceptions. J Clin Oncol 2000;18:2515 – 2521.
  9. Low Dog T. Traditional and alternative therapies for breast cancer. Altern Ther Health Med 2001; 7:36-47.
  10. Tamayo C, Richardson M. Presentation at 36th Annual Drug Information Association Meeting. Baltimore, MD, June 17-21, 1999.
  11. Morita H, et al. Cytotoxic and mutagenic effects of emodin on cultured mouse carcinoma FM3A cells. Mutat Res 1988;204:329-32.
  12. Ulbricht C, Weissner W, Hashmi S, Rae Abrams T, Dacey C, Giese N, Hammerness P, Hackman DA, Kim J, Nealon A, Voloshin R. Essiac: systematic review by the natural standard research collaboration. J Soc Integr Oncol 2009;7(2):73-80.
  13. Zick SM, Sen A, Feng Y, Green J, Olatunde S, Boon H. Trial of Essiac to ascertain its effect in women with breast cancer (TEA-BC). Journal of Alternative and Complementary Medicine 2006;12(10):971-80.
  14. Hutchinson DJ. Experimental Chemotherapy, Memorial Sloan-Kettering Cancer Center, Rye, N, personal communication, September 26, 1988 and March 1989.
  15. Glun GL. Essiac. Nature’s cure for cancer. Wildfire 1991:6:48-55.
  16. Foldeak S, Dombradi GA. Tumor-Growth Inhibiting Substances of Plant Origin. I. Isolation of the Active Principle of Arctium lappa. Acta Phys Chem 1964;10:91- 93.
  17. Dombradi CA, Foldeak S. Screening Report on the Antitumor Activity of Purified Arctium Lappa Extracts. Tumori 1966;52:173.
  18. Itokawa H, Watanabe K, Mihara K. Screening Test for Antitumor Activity of Crude Drugs (2). Shoyakugaku Zasshi 1982;36:145-9.
  19. Woo WS, Lee EB, Chang I. Biological Evaluation of Korean Medicinal Plants. II. Yakhak Hoe Chi 1977;21:177-183.
  20. Morita K, Kada T, Namiki M. A desmutagenic factor isolated from burdock (Arctium lappa Linne). Mutat Res 1984;129:25-31.
  21. US Congress, Office of Technology Assessment: Unconventional Cancer Treatments. Washington, DC: U.S. Government Printing Office, 1990. OTA-H-405, pp 71-5.
  22. Belkin M, Fitzgerald DB. Tumor-Damaging Capacity of Plant Materials. 1. Plants Used as Cathartics. J Natl Cancer Inst 1952;13:139-155.
  23. Kupchan SM, Karim A. Tumor inhibitors. 114. Aloe emodin: antileukemic principle isolated from Rhamnus frangula L. Lloydia 1976;39:223-4.
  24. Pettit GR, Blazer RM, Reierson DA. Antineoplastic agents. 51. The yellow jacket Vespula pensylvanica Lloydia 1977;40(3):247-52.
  25. Leonard BJ, Kennedy DA, Cheng FC, Chang KK, Seely D, Mills E: An in vivo analysis of the herbal compound essiac. Anticancer Res 2006; 26(4B):3057-3063.
  26. Kulp KS, Montgomery JL, Nelson DO, Cutter B, Latham ER, Shattuck DL, Klotz DM, Bennett LM. Essiac and Flor-Essence herbal tonics stimulate the in vitro growth of human breast cancer cells. Breast Cancer Res Treat 2006; 98(3):249-59.
  27. Seely D, Kennedy DA, Myers SP, Cheras PA, Lin D, Li R, Cattley T, Brent PA, Mills E, Leonard BJ: In vitro analysis of the herbal compound Essiac. Anticancer Res 2007; 27(6B):3875-3882.
  28. Eberding A, Madera C, Xie S, Wood CA, Brown PN, Guns ES: Evaluation of the antiproliferative effects of Essiac on in vitro and in vivo models of prostate cancer compared to paclitaxel. Nutr Cancer 2007; 58(2):188-196.
  29. Rodriguez P, Blanco J, Juste S, et al. Allergic contact dermatitis due to burdock (Arctium lappa). Contact Dermatitis 1995;33:134-5.
  30. Schulz V, Hansel R, Tyler VE. Rational Phytotherapy: A Physician's Guide to Herbal Medicine. Terry C. Telger, transl. 3rd ed. Berlin, GER: Springer, 1998.
  31. Natural Medicines Comprehensive Database. Essiac. https://naturalmedicines.therapeuticresearch.com/ (accessed 8 February 2017).
  32. Sasaki Y, Kimura Y, Tsunoda T, Tagami H. Anaphylaxis due to burdock. Int J Dermatol 2003;42:472-3.
  33. Gruenwald J, Brendler T, Jaenicke C. PDR for Herbal Medicines. 1st ed. Montvale, NJ: Medical Economics Company, Inc., 1998.
  34. McGuffin M, Hobbs C, Upton R, Goldberg A, eds. American Herbal Products Association's Botanical Safety Handbook. Boca Raton, FL: CRC Press, LLC 1997.
  35. Brinker F. Herb Contraindications and Drug Interactions. 2nd ed. Sandy, OR: Eclectic Medical Publications, 1998.
  36. Newall CA, Anderson LA, Philpson JD. Herbal Medicine: A Guide for Healthcare Professionals. London, UK: The Pharmaceutical Press, 1996.
  37. Bolton-Smith C, Price RJ, Fenton ST, et al. Compilation of a provisional UK database for the phylloquinone (vitamin K1) content of foods. Br J Nutr 2000;83:389-99.
  38. Tice J, Cummings SR, Ettinger B, et al. Few adverse effects of two red clover extracts rich in phytoestrogens: a multicenter, placebo-controlled trial. Alt Ther Health Med 2001;7:S33.
  39. Nelsen J, Barrette E, Tsouronix C, et al. Red clover (Trifolium pratense) monograph: A clinical decision support tool. J Herbal Pharmacotherapy 2002;2:49-72.
  40. This P, De La Rochefordiere A, Clough K, et al. Phytoestrogens after breast cancer. Endocr Relat Cancer 2001;8:129-34.
  41. Baker DH. Iodine toxicity and its amelioration. Exp Biol Med (Maywood) 2004;229:473-8.
  42. Phaneuf D, Cote I, Dumas P, et al. Evaluation of the contamination of marine algae (Seaweed) from the St. Lawrence River and likely to be consumed by humans. Environ Res 1999;80:S175-S182.