Mistletoe has been used as a medicinal plant since ancient times. Weleda co-founder Dr. Rudolf Steiner first suggested it specifically for cancer patients in the early 20th century, and with increasing successes in treatment since that time, its use has become widespread. In fact, over 50% of cancer patients in Germany are treated with the plant in some form during their treatment.

Mistletoe grows on a variety of host trees, each of which yields a different type of Iscador^® — Iscador^® P from pine trees, Iscador^® Q from oak trees, and Iscador^® M from apple trees. The different formulations are each prescribed to treat different forms of cancer.