Cancer Research UK say that milk thistle is promoted on the internet for its claimed ability to slow certain kinds of cancer, but that there is no good evidence in support of these claims.[83] Mistletoe (or Iscador) – a plant used in anthroposophical medicine, proposed as a cancer cure by Rudolf Steiner (1861–1925), who believed it needed to be harvested when planetary alignment most influenced its potency. According to the American Cancer Society, "available evidence from well-designed clinical trials does not support claims that mistletoe can improve length or quality of life".[84]