Not Just for Christmas: Mistletoe in Integrative Cancer Care

How this plant-based supports well-being and quality of life in cancer

Mistletoe is one of the most commonly prescribed herbal medicines in integrative cancer care and included in standard treatment in some European hospitals.

When given as an injection just under the skin (subcutaneously), mistletoe helps activate and modulates the innate immune system.

It enhances immune response by increasing white blood cells and natural killer (NK) cells, releasing anti-tumor cytokines and beta-endorphins. NK cells, often reduced by radiotherapy and chemotherapy, play an essential role in recognising and breaking down cancer cells.

Evidence Supporting Mistletoe

Over 150 clinical studies, including randomised controlled trials and meta-analyses, have investigated the use of mistletoe as a supportive therapy in cancer care. Despite some methodological limitations, studies report reduced adverse effects from chemotherapy and radiotherapy – and, in early studies, immunotherapy – along with improvements in patients’ quality of life.[i] [ii] [iii]

Mistletoe as a Medicinal Plant

Mistletoe (Viscum album L.) has a well-established tradition in supportive cancer care, with over 100 years of consistent use.

The concentration of active substances in mistletoe varies depending on the host tree and the season.  Birds consume the white berries and help disperse the plant. Mistletoe absorbs water, minerals, and nutrients through its haustorium, which anchors it to the host tree and contributes to its tree-dependent characteristics. The plant is typically harvested at selected times of the year to ensure a varied composition of constituents, including viscotoxins and lectins, in different extracts.

Restoring Natural Rhythms

Mistletoe helps regulate and normalise body temperature and circadian rhythms, improving inner warmth and restorative functions such as sleep.

Mistletoe can be used as therapy at any stage of cancer to improve energy, appetite, mood, and overall well-being.

An Integrative and Individualised Approach

As an integrative therapy, mistletoe is prescribed within a patient-centred, evidence-informed approach to ensure safe and effective use alongside other treatments.  The selection and prescription of mistletoe take into account individual factors such as constitution, overall health, disease stage, and any coexisting health conditions.

Additionally, the active substances within the plant, as well as the specific type and site of the cancer, are carefully considered.

Manufacture and Prescription

Subcutaneous mistletoe preparations are produced by four manufacturers: Iscador AG, Abnoba GmbH, Helixor GmbH, and Wala Heilmittel GmbH.

The mistletoe plant is sustainably harvested from natural habitats in Switzerland, Germany, and France.

Mistletoe is a prescription-only medicine in the UK and is not funded by the NHS.  It is typically administered subcutaneously two to three times a week in a rhythmic pattern and often takes time to reach a therapeutic dose.

Other methods, such as injection directly into a tumour or off-label intravenous infusion given into a vein, may be considered for selected individuals under appropriate clinical supervision.

Many patients ask whether mistletoe can be taken by mouth. Although available in some countries as anthroposophic medicines, oral preparations have not been thoroughly studied for use in cancer care.

There are thirteen different preparations, five common types being Fir (Abietes) and Pine (Pinus) from coniferous trees, and Apple (Malus, M), Oak (Quercus, Qu), and Ash (Fraxini) from deciduous host trees. Due to differences in extraction methods, each host-tree type from each manufacturer should be considered a distinct preparation.

Safety

There are no known adverse interactions with standard cancer treatments and chemotherapeutic agents. Emerging observational data suggests potential benefits with immunotherapy; however, prospective randomised trials are needed to confirm these findings.[iv] Allergies to mistletoe are rare. Generalised side effects are usually dose-related rather than true allergic reactions and typically resolve with dose adjustment.

It is important to emphasise that mistletoe is an integrative therapy, not an alternative for standard cancer treatments, and should be prescribed by a trained clinician. Although generally well tolerated, its use should first be discussed with the patient’s oncology team.

Dr Roger Smith, MBBS, MRCP (UK), Dip Integrative Medicine

Integrative Medicine doctor at the National Centre for Integrative Medicine (NCIM) and an NHS Consultant specialising in supportive care for people living with cancer

[i] Loef, M. and Walach, H., 2020. Quality of life in cancer patients treated with mistletoe: a systematic review and meta-analysis. BMC Complementary Medicine and Therapies, 20, pp.1-14.

[ii] https://www.mistletoe-therapy.org/scientific-information

[iii] Thronicke, A., Steele, M.L., Grah, C., Matthes, B. and Schad, F., 2017. Clinical safety of combined therapy of immune checkpoint inhibitors and Viscum album L. therapy in patients with advanced or metastatic cancer. BMC Complementary and Alternative Medicine, 17, pp.1-10.

[iv] Schad, F., Thronicke, A., Hofheinz, R.D., Matthes, H. and Grah, C., 2024. Patients with Advanced or Metastasised Non-Small-Cell Lung Cancer with Viscum album L. Therapy in Addition to PD-1/PD-L1 Blockade: A Real-World Data Study. Cancers, 16(8), p.1609.