Nausea and vomiting are the only reported adverse effects associated with the use of Essiac. Reviewed in  The manufacturer of Flor Essence states that users may experience increased bowel movements, frequent urination, swollen glands, skin blemishes, flu-like symptoms, or slight headaches.
- Herbal treatments. In: US Congress, Office of Technology Assessment.: Unconventional Cancer Treatments. Washington, DC: U.S. Government Printing Office, 1990. OTA-H-405, pp 71-5. Also available online. Last accessed August 10, 2012.
- Flora Flor•Essence®. Burnaby, Canada: Flora Manufacturing & Distributing Ltd. Available online. Last accessed August 10, 2012.