Essiac

# Overview
Essiac or Essiac Tea is a blend of herbs used to make a tea that is believed by some and questioned by others to have cancer-treating properties. It was discovered by a Canadian nurse, Rene Caisse, who named it after her last name spelled backwards. The original formula is believed to have its roots in native Canadian Ojibwa medicine and contains greater burdock root (Arctium lappa), slippery elm inner bark (Ulmus rubra, formerly known as Ulmus fulva), sheep sorrel (Rumex acetosella), and Indian or Turkish rhubarb root (Rheum officinale).

# Effectiveness
With respect to the use of Essiac in treating cancer, the U.S. National Institutes of Health's Medline states that as of early 2008:
Currently, there is not enough evidence to recommend for or against the use of this herbal mixture as a therapy for any type of cancer. Different brands may contain variable ingredients, and the comparative effectiveness of these formulas is not known. None of the individual herbs used in Essiac has been tested in rigorous human cancer trials (rhubarb has shown some anti-tumor properties in animal experiments; slippery elm inner bark has not; sheep sorrel and burdock have been used traditionally in cancer remedies). Numerous individual patient testimonials and reports from manufacturers are available on the Internet, although these cannot be considered scientifically viable as evidence. Individuals with cancer are advised not to delay treatment with more proven therapies.

# History
Caisse set up a free clinic in Bracebridge, Ontario which ran from 1934 to 1942. During that time a number of petitions were presented to the Legislature in Ontario, in 1938 calling for Rene to be allowed to practice throughout Ontario, but such permission was not granted.
Medline notes there are more than 40 different essiac-like products now being sold in North America, Europe, and Australia. One of these alternative preparations contains eight herbs,  adding red clover (Trifolium pratense), watercress (Nasturtium officinale), blessed thistle (Cnicus benedictus), and kelp (Laminaria digitata) to the original four ingredients. Other preparations add echinacea and black walnut (Juglans nigra) or other ingredients, such as cat's claw ( Uncaria tomentosa ).
According to Medline, based on tradition, some people take essiac tea on occasion for general health purposes, detoxification, or for healing of various ailments other than cancer. Some of these other ailments include AIDS, asthma, chronic fatigue syndrome, diabetes, immune system disorders, liver problems, Lyme disease, and lupus erythematosus. NIH's Medline says even less evidence is available for these applications than for cancer.
Updating the history of Essiac, Medline says:
In the 1970s, Caisse provided the formula to Resperin Corporation Ltd., with the understanding that Resperin would coordinate a scientific trial in humans. Although a study was initiated, it was stopped early amidst questions of improper preparation of the formula and inadequate study design. This research was never completed. Resperin Corporation Ltd., which owned the Essiac name, formally went out of business after transferring rights to the Essiac name and selling the secret formula to Essiac Products Ltd., which currently distributes products through Essiac International.