I'm not at all surprised that your father had great results from the use of Esiac. I've posted previously regarding the ability of oxalic acid foods, beverages, etc., to combat cancer. Essiac tea contains strong oxalic acid herbs. If you go to www.coljoe.com you will understand why the addition of calcium blocks the action of the Essiac and other known foods that fight cancer. Calcium should never be ingested alone. It is best absorbed by the body when nutritionally and naturally balanced, i.e., in the form of almonds, beans, cabbage. Supplements are not balanced. Cow milk is also unbalanced given the amount of calcium in relationship to the magnesium present. I don't doubt that your father will continue to improve if he takes in calcium only through plant and seed/nut sources.