Anecdotally, testimonials for Essiac tea include reduction of various forms of cancer, alleviating neuropathy or chronic pain, improvement of circulation, reduction in eczema and elimination of Lyme disease. However, as of 2016, WebMD reports that no peer-reviewed controlled trials have proven positive effects of Essiac tea on various health conditions.
Anecdotal testimonials include individuals that had some form of serious or malignant cancer such as colon, lung, esophageal, lymphatic or ovarian cancer being reduced or going into remission. Other anecdotal testimonials include improvement from symptoms of neuropathy, hot flashes, chronic pain and skin problems.
However, scientific studies have not proven Essiac tea's effectiveness for health conditions. For example, according to Cancer.gov, although Essiac was initially promoted as a cancer treatment in the 1920s, clinical studies performed in the 1980s failed to show anticancer activity in animal studies.
CancerTutor.com notes that Essiac tea may be dangerous for pregnant or nursing mothers, those with kidney disease, high levels of iron or bowel obstructions. It also notes that it may be dangerous for those with tumors near a major blood supply or in the brain.