Although nowadays associated with romantic Christmas traditions, its advisable that those found kissing under the mistletoe this December do not reach up and have a munch of this parasitic plant which grows on the branches of other trees. Mistletoe contains a number of constituents, including viscotoxins (small proteins similar to cobra venom) and phoratoxins which are cardio toxins, and alkaloids which effect the gastrointestinal tract. High doses have been reported as harmful to human health. However, mistletoe extracts have found therapeutic use, such as reducing side effects of chemotherapy in cancer patients. So mistletoe is more than just a festive and romantic plant!