Viscaceae
Viscum album
Mistletoe · European mistletoe
- Part used
- aerialleaf
- Native range
- Europe and western Asia
- Morphology
- An evergreen hemiparasitic shrub forming spherical clumps in the branches of host trees, with paired leathery leaves, forked stems and sticky white berries. It photosynthesises but takes water and minerals from its host.
What is in it
Evidence
Extensively studied as a cancer treatment. Cochrane reviews and systematic assessments find no reliable evidence of benefit on survival, and the better-designed trials are negative. Some trials report quality-of-life improvement, from studies with high risk of bias.
Safety
Berries and leaves are toxic on ingestion, causing gastrointestinal upset and, in quantity, cardiovascular effects. Injectable preparations cause local inflammation and fever, and anaphylaxis is reported. The graver harm is delay: mistletoe used instead of oncological treatment.
Interactions: Additive with antihypertensives; Immunomodulatory; caution with immunosuppressants
Regulatory: Injectable mistletoe is a registered medicine in Germany, Switzerland and Austria. Not registered for cancer treatment in Australia.
How the traditions classify it
Three systems, rating the same plant. Where they disagree, none of them is correcting the others — they are separate frameworks that arrived at their categories independently.
Historical use
A ritual plant across northern Europe long before it was a medicine. Its use in cancer treatment is entirely modern: Rudolf Steiner proposed it in 1917 on anthroposophical reasoning, and injectable mistletoe preparations have been used in German-speaking Europe ever since.
Recorded as history and attributed where possible. Long use establishes that a plant was widely used, not that it worked, and not that it was safe.
Worth knowing
Its family is the fourth disputed placement in this collection. APG folds the mistletoes into a broadly drawn Santalaceae with the sandalwoods, which most recent references follow; GBIF and Kew keep Viscaceae as a family in its own right. As with elder, Rehmannia and Syrian rue, this entry follows its stated authority — and the recurring shape of the disagreement is worth noticing: it is almost always a broad APG family against a narrower traditional one, and which you meet depends entirely on which reference you happened to open.
Mistletoe is the most widely used complementary cancer treatment in German-speaking Europe, it is reimbursed by some insurers, and it does not work.
Its origin is not traditional at all. Rudolf Steiner proposed it in 1917 by anthroposophical analogy — mistletoe is a parasite growing without roots in a host, tumours grow without regard to the body, and like should treat like. That reasoning is the same family as the doctrine of signatures, and it is the whole basis of the treatment.
The evidence has been examined thoroughly because so many people use it. Survival benefit has not been demonstrated in the trials with adequate design, and Cochrane's assessment is unambiguous. What keeps it in use is a combination of institutional momentum, quality-of-life claims from weak studies, and the fact that being offered something matters enormously to a frightened person.
That last point is real and is why this entry is not written dismissively. The harm is not the injection; it is the person who chooses it instead.
Nomenclature verified against GBIF backbone taxonomy.