Viscum album L extracts (VAE, mistletoe) and isolated mistletoe lectins (ML) have immunostimulating properties and a strong dose-dependent cytotoxic activity. They are frequently used in complementary cancer treatment, mainly to improve quality of life, but partly also to influence tumour growth, especially by injecting VAE locally and in high dosage. The question is raised whether these higher dosages can induce any harm or immunosuppressive effects.

Citation: Kienle, G. S., Grugel, R., & Kiene, H. (2011). Safety of higher dosages of Viscum album L. in animals and humans—Systematic review of immune changes and safety parameters. BMC Complementary and Alternative Medicine, 11(1), 72. https://doi.org/10.1186/1472-6882-11-72