Historically, only two of the plants, Arctium lappa (Burdock Root) and Ulmus fulva (Slippery Elm Bark) have any recorded use by Native cultures anywhere in North America.  However, wild rhubarb was available and Sheep sorrel was a common indigenous weed throughout the North American continent.

I obtain these herbs from U.S. certified organic herb growers and processors. I never use imported herbs, which must be sterilized before being allowed into U.S. Herbs ordered from me have vacuum sealed and special light-resistant protection.

Sheep sorrel is the critical ingredient in this tea. It has either been grown on an organic farm in acidic soil using no pesticides/fertilizers, or it has been wildcrafted. The resulting tea product must fall within a certain acidic range in order to pass stringent California Food & Drug inspection (three separate tests are done on my tea). I know when I receive either the wrong herb or herbs of poor quality because the testing procedures would reflect such. Therefore, it is very crucial for me to deal with ethical, honest herb growers who understand the need for the sheep sorrel to come from acidic soil in order for the plant to retain its vital components.

Essiac tea is classified as a decoction. According to Richard Mabey (The New Age Herbalist, 1988), "decoctions are used mainly for the woodier parts of plants and the roots, and involve boiling them in water for about 15 minutes; they are ideal for extracting bitter principles and mineral salts". Infusions aren't boiled, the herbs (or tea bag, tea ball) are put in a cup and very hot water is poured over them. Infusions are usually made with aerial parts of an herb (leaves, stems or flowers). This recipe calls for the herbs to be simmered for 10 minutes, so it is a decoction.

Machine milling or grinding of herbs to a fine powder is very hard on them, and by using powdered herbs, one will be taking a chance of losing active constituents. Therefore, and because Rene was unschooled on proper herbal techniques, I use cut and sifted herbs.