abstract:Essiac, marketed as Flor Essence and several other brands, is an herbal tea promoted as an alternative treatment for cancer and other illnesses; however, the evidence goes against such claims. As with many alternative remedies, the exact composition of essiac is unclear, but it reportedly contains burdock (Arctium lappa), Indian rhubarb, sheep sorrel (Rumex acetosella), and slippery elm bark (Ulmus rubra).