Mistletoe (Viscum album) is a plant that grows on several different trees throughout the world. The berry, leaf, and stem are used as medicine.

European mistletoe contains chemicals that might stimulate the immune system and kill certain cancer cells, but it’s not clear if these effects occur in the human body. People use European mistletoe for various types of cancer, including head and neck cancer, bladder cancer, breast cancer, lung cancer, and many other conditions.