Essiac/Flor Essence (PDQ®): Complementary and alternative medicine - Health Professional Information [NCI] - General Information
Essiac and Flor Essence are administered orally in the form of herbal teas.[1,11] Reviewed in [4,6,8,9,18] Originally, an extract of one of the herbs (not specified) was administered to cancer patients by intramuscular injection at or near tumor sites, and the other herbs were administered orally as a tea. Reviewed in [4,8,9,18]
Only minimal information about dose and schedule of administration is freely available from the manufacturer of Essiac. According to the manufacturer, the dose will vary, depending on the reason for ingestion; the manufacturer's recommended schedules of administration assume a 12-week program of uninterrupted use. Although Essiac is said to be safe for pets, no information is given about its safety in children.
The manufacturer of Flor Essence states that adults may consume from 30 to 360 mL (i.e., 1–12 fl oz) of Flor Essence tea a day, depending on individual requirements, and that it may be used on an ongoing basis. The manufacturer also suggests that Flor Essence may be safely consumed by infants and children, but its use by pregnant women and nursing mothers is not recommended. The promotion of mammary tumors observed in a rat model of breast cancer raises the theoretical concern that Flor Essence may impact normal mammary ductal development during childhood, thereby raising concern about its use at this time.
The manufacturers of Essiac and Flor Essence both state these products can be used in conjunction with other cancer treatments.[1,11] Nonetheless, some proponents of Essiac have recommended that no additional anticancer therapy (such as chemotherapy or radiation therapy) be undertaken while patients are being treated with the mixture. Reviewed in  The purported rationale for this statement is that conventional anticancer treatments may alter immune system function and prevent Essiac from working effectively. Reviewed in  As indicated previously, no evidence has been reported in the peer-reviewed scientific literature to show that Essiac is an effective treatment for patients with cancer.
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- Essiac. Toronto, Canada: Canadian Breast Cancer Research Alliance, 1996.
- The History of Essiac & Rene Caisse, Canada's Cancer Nurse. Kirkland, Canada: Altramed Health Products, 2001. Available online. Last accessed August 10, 2012.
- Flora Flor•Essence®. Burnaby, Canada: Flora Manufacturing & Distributing Ltd. Available online. Last accessed August 10, 2012.
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- Ottenweller J, Putt K, Blumenthal EJ, et al.: Inhibition of prostate cancer-cell proliferation by Essiac. J Altern Complement Med 10 (4): 687-91, 2004.
- LeMoine L: Essiac: an historical perspective. Can Oncol Nurs J 7 (4): 216-21, 1997.
- Bennett LM, Montgomery JL, Steinberg SM, et al.: Flor-Essence herbal tonic does not inhibit mammary tumor development in Sprague Dawley rats. Breast Cancer Res Treat 88 (1): 87-93, 2004.