H,
"In 1922, a public health nurse named Rene Caisse from Ontario, Canada learned about Essiac from one of her patients who claimed to have recovered from breast cancer by taking an Indian herbal tea developed by an Ojibwa medicine man. She obtained the recipe and reportedly treated her aunt's stomach cancer with the tea. In 1924, Caisse opened a clinic and began to offer cancer patients the herbal mixture, which she named Essiac (her last name spelled backwards)."
The main ingredients are burdock root, slippery elm bark and sheep sorrel.
The Japanese eat a lot of burdock root and believe the long root promotes long life. It has never been scientifically proven but is more folk lore. Slippery elm bark has been used by eastern culture and native americans for centuries in a variety of forms. It is believed to sooth irritation and inflamation of mucous membranes and to reduce inflamation when made into a salve. Sheep Sorrel is high in oxalic acid, sodium, potassium, iron, manganese, phosphorous, beta carotene, and vitamin C.
If your beliefs allow ingesting of foods and herbs to promote health, the three above may have uses. However, as a medicine, better leave that to the pharmaceutical experts.
I prefer to eat foods that contain things that many herbal supplements intend to provide. For example, flax seed oil in smoothies, high omega-3 eggs, sushi, etc., for my omega-3, drinking green tea for 40 years, eating green leafy vegetables as often as possible and finding good recipes for a variety of vegetables.
It's sad when people take something they see or read and extrapolate that into a "cure" for anything. If cures were that easy, we wouldn't have such ailments everywhere we turn.
My two cents worth only.
Ed