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Cancer Health Center

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Essiac/Flor Essence (PDQ®): Complementary and alternative medicine - Health Professional Information [NCI] - General Information


Essiac and Flor Essence are sold worldwide as health tonics or herbal dietary supplements.[1,10,2,3,4,9] In the United States, health tonics and dietary supplements are regulated as foods, not drugs. Therefore, premarket evaluation and approval by the U.S. Food and Drug Administration (FDA) are not required, and specific disease treatment or prevention claims are not allowed. Because health tonics and dietary supplements are not formally inspected for manufacturing consistency, there may be considerable variation from lot to lot, and there is no guarantee that ingredients identified on product labels are present at all or are present in the specified amounts. The FDA has not approved the use of either Essiac or Flor Essence for the treatment of patients with cancer or any other medical condition.

To conduct clinical drug research in the United States, researchers must file an Investigational New Drug (IND) application with the FDA. An IND application must also be made for clinical evaluation of dietary supplements as agents for the treatment or prevention of disease. The FDA's IND process is confidential, and the existence of an IND application can be disclosed only by the applicants. To date, no investigator has announced filing an IND application to study either Essiac or Flor Essence in the treatment of patients with cancer.

Essiac and Flor Essence are administered orally in the form of herbal teas.[1,4,6,7,8,10,17] 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.

Only minimal information about dose and schedule of administration is freely available from the manufacturer of Essiac.[1] 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.[1] Although Essiac is said to be safe for pets, no information is given about its safety in children.[1]

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.[10] 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.[10] 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.[18]

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