Mistletoe Therapy Explained Simply

1. What It Is About

Mistletoe therapy uses extracts from the European mistletoe (Viscum album). Mistletoe is a shrub that grows on other trees and extracts water and nutrients from them. Aqueous extracts are prepared from the leaves and stems. These are usually injected under the skin, sometimes into a vein or directly into the tumour. The preparations contain varying amounts of mistletoe lectins and viscotoxins – proteins found in mistletoe. The quantities differ depending on the tree on which the mistletoe grew and when it was harvested. The therapy is part of anthroposophic medicine but is also used independently. In cancer therapy, it is often used in addition to surgery, chemotherapy or radiation.

2. What Studies Show

Quality of life is the best-studied outcome. A large review from 2010 analysed 26 controlled studies in cancer patients. Twenty-two of these reported improvements in quality of life under mistletoe therapy – particularly in fatigue, sleep, nausea, appetite and mood. Even studies with better methodological quality showed these benefits 1. A further review from 2020 confirmed that, across multiple studies, patients felt better under mistletoe therapy 5. In a study of 32 stomach cancer patients after surgery, general health improved after 24 weeks, and diarrhoea occurred less frequently (7 % vs. 50 %) 7. A study of 220 patients with advanced pancreatic cancer found that those receiving mistletoe therapy lived on average 4.8 months, compared with 2.7 months in the control group 2. Other studies did not show such a survival advantage. A large study of 830 melanoma patients after surgery found no difference in disease-free or overall survival 3. A study of 477 patients with head and neck tumours also found no differences 4. In a further study, mistletoe therapy was associated with fewer dose reductions of chemotherapy (13 % vs. 44 %), fewer severe side effects (16 % vs. 41 %) and fewer hospital admissions (24 % vs. 54 %) 6. Tolerability is generally good: a 2011 review of 69 clinical trials and 48 animal studies found mostly mild side effects such as flu-like symptoms, fever or reactions at the injection site. Severe reactions such as allergic responses are rare 8.

3. What Remains Unclear

Whether mistletoe therapy extends life is not clear. Some studies suggest a benefit, while others – including those with stricter methodology – find none. Often, blinding (i.e. neither patient nor physician knowing who receives mistletoe therapy) and sufficiently large sample sizes are lacking. The extracts are also prepared differently, making comparisons difficult. It is also unclear whether the observed improvements in quality of life are directly due to mistletoe or to other factors such as increased attention. Long-term safety data, especially in combination with other cancer therapies, are still lacking. The dose-response relationship and how well the active ingredients are absorbed by the body are only partially understood.

4. What This Means in Practice

Mistletoe therapy is often used alongside cancer treatment to alleviate symptoms such as fatigue, nausea or loss of appetite. The evidence is strongest for quality of life, less so for survival. Anyone considering mistletoe therapy should discuss it with their cancer care team, as interactions with other therapies are possible. The decision should be based on personal circumstances and available information. It is important to know that mistletoe therapy does not replace cancer treatment but can complement it. What needs to be clarified next: Large, well-designed studies with standardised preparations and long-term follow-up to determine in which cancer types and at which stages mistletoe therapy is most beneficial.

All details with study numbers and sources: detailed page on mistletoe therapy. For children: Mistletoe therapy for children.