Written by Mirjam Wuesthof and the CAM-Cancer Consortium.
Updated January 19, 2015

Mistletoe (Viscum album)

What is it?

Scientific name/brand name/common name

Mistletoe (Viscum album) is a semiparasitic plant that grows on leaf-bearing and coniferous trees throughout Europe, Asia and North Africa. Most commonly it grows on poplar, apple tree, fir and pine but also oak and several other common trees 1. Currently available preparations of various forms of mistletoe extract are ABNOBAViscum® (Abnoba), Helixor® (Helixor), Iscador® (Weleda), Iscucin® (Wala), Lektinol® (Madaus).

Ingredients

Mistletoe extracts contain several pharmacologically active substances: mistletoe lectins, viscotoxins, flavonoids, terpenoids, alkaloids and amines 2. The composition of an extract may vary according to season, host tree, parts of the plant used and extraction method. Some preparations are, therefore, standardized to the content of mistletoe lectins (Lektinol®).

Application and dosage

Mistletoe is usually injected subcutaneously, but other routes of administration (e.g. intravenous, peritumoural, or intrapleural) also exist. The dosing regimens vary according to extract type and either follow a constant or a variable dose. In most cases, subcutaneous injections are given 2 to 3 times a week, but the overall duration of treatment varies considerably.

History and providers

Mistletoe has been used medicinally for centuries and has been employed to treat a variety of diseases. Recent interest in mistletoe began in the 1920s after it was first proposed for the treatment of cancer by Rudolf Steiner, the founder of anthroposophy and anthroposophical medicine. Since the 1980s, mistletoe therapy has been researched systematically. A number of German phyto-pharmacological providers like ABNOBA, HELIXOR, MADAUS, WELEDA and WALA market a range of different mistletoe preparations. Some products are anthroposophical (ABNOBAViscum®,  Helixor®, Iscador®, Iscucin®), whereas Lektinol® is a phytotherapeutical product. Mistletoe extracts are prepared as aqueous solutions and they can be fermented or unfermented. Some extracts, e.g. Iscucin are prepared according to homeopathic principles. Indications within the anthroposophical approach depend on the host tree of the mistletoe plant.

Claims of efficacy / alleged indication

Providers claim that supportive cancer treatment with mistletoe improves quality of life in cancer patients. Further, some proponents claim that mistletoe enhances cancer remission and survival rates. Main indications are solid tumours with the exception of primary brain tumours and cerebral metastases because of the increased risk of perifocal oedemas.

Mechanisms of action

Mistletoe holds interest as a potential anticancer agent because extracts and their constituents, mainly lectins and viscotoxins, have been shown to kill cancer cells in vitro 3-8, to stimulate immune system cells both in vitro and in vivo 9-14 and to have other mechanisms of action, such as antiangiogenesis 15. In view of mistletoe’s ability to stimulate the immune system through induction of several cytokines and activation of lymphocytes, granulocytes and phagocytes, it has been classified as a type of biologic response modifier 16-18.

Prevalence of use

Mistletoe is popular in Europe, particularly in Germany and Switzerland. Studies conducted in these countries showed that 16% of patients with a history of early breast cancer and 15% of lung cancer patients used mistletoe preparations, mostly in order to "support the tumour treatment" 19,20. The prevalence of usage shows clear national differences.

Legal issues

In Germany, Switzerland and Austria, mistletoe preparations are licensed medicines that are partly reimbursable through the official healthcare system. In other European countries, they are not licensed. In the United States, the FDA presently does not allow the importation or distribution of injectable preparations of mistletoe, including homeopathic formulations, except for the purpose of clinical research. The Medicines and Healthcare Regulatory Agency in the UK states that, if a company places a manufactured herbal remedy on the market and supplies the product to herbalists, then such a product would need to have either a marketing authorisation or traditional use registration. This is in accordance with the European Directives and Regulation of herbs.

Costs and expenditures

The costs of extracts vary. In Germany, a course of treatment lasting 2-3 weeks would cost around Eur 60. 

Citation

Mirjam Wuesthof, CAM-Cancer Consortium. Mistletoe (Viscum album) [online document]. http://cam-cancer.org/The-Summaries/Herbal-products/Mistletoe-Viscum-album. January 19, 2015.

Document history

Summary fully revised and updated in January 2015 by Mirjam Wuesthof.

Summary first published in March 2011, authored by Edzard Ernst.

References

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