Mistletoe and cancer treatment – what do research and experts say?

More and more cancer patients, in addition to standard therapies, are looking for additional options that could help them fight the disease. One of the most frequently mentioned plants in this context is Viscum album - also known as mistletoe.

But does it really make sense to use mistletoe in the treatment of cancer? What does science say about it, and what does practice say? In this article, we present an objective review of the available data – without sensationalism, but without dismissing the potential benefits either.

What exactly is mistletoe?

Mistletoe is a semi-parasitic plant that grows on the trunks of trees such as apple, oak, and pine. It has been used in phytotherapy for centuries, and in modern medicine, its extracts standardized for medical use are particularly prominent – known under names such as Iscador, Helixor, AbnobaVISCUM, and others.

Mistletoe extracts contain substances such as lectins, viscotoxins, polysaccharides, and other bioactive molecules that are thought to be able to affect the immune system, and in some cases, have mild cytotoxic effects.

In conversations with patients, mistletoe is often mentioned as a plant that “helps with cancer” – but this name in popular use can refer to several completely different plants, which can easily lead to confusion. If you hear about “mistletoe”, it is important to check which plant it is. Only the plant Viscum album (white mistletoe) has scientifically researched effects in oncological practice. Other species – including Arum maculatum – are not safe or proven to be useful in cancer.

Popular name	Latin name	Description and use
Mistletoe	Viscum album	An evergreen plant with white berries, growing on trees. The only one with clinically tested extracts in oncology (e.g. Iscador, Helixor).
Yellow kozlac	Loranthus europaeus	It grows on oak, similar to mistletoe, but without clinically confirmed use in the treatment of cancer.
Snakeroot	Arum maculatum	A plant with broad leaves and red berries. Poisonous! It has no medical use in oncology.
Kozlac from Hilandar	(unknown mixture)	Mostly tincture from a monastery pharmacy. It is not standardized or scientifically researched. The composition is often not clearly declared.

Is there any evidence that "Kozlac s Hilandar" helps with cancer?

Patients in the Balkans often ask questions about Kozlac from Hilandar, so we dedicate an additional explanation to it, without the intention of deliberately speaking negatively about any product, including this one. No - there are no available scientific studies to confirm that this particular preparation has an effect in oncological diseases.

This does not mean that it does not subjectively help some people (placebo, emotional peace, personal faith...), but from a medical perspective:

• not a standardized preparation,

• has not been tested for safety or effectiveness,

• There are no known interactions with oncological drugs.

Clinical difference - "Kozlac from Hilandar" vs. "standardized mistletoe extract":

Feature	Kozlac from Hilandar	Standardized extracts (e.g. Iscador, Helixor)
Herbal base	Unknown (often not clearly declared)	Viscum album (white mistletoe)
Form	Tincture, tea, syrup	Sterile subcutaneous solution
Quality control	No publicly available data	Strict pharmaceutical control
Researched in medicine	Not	Yes, more than 100 studies
Application in oncology	Not recommended	Possible with supervision, as supportive therapy

How does mistletoe work for oncology patients?

Some research shows that mistletoe preparations can:

• stimulate the immune response (activation of NK cells, monocytes, lymphocytes),

• have anti-inflammatory and antioxidant effects,

• potentially reduce the side effects of chemotherapy and radiation,

• improve quality of life (energy, appetite, sleep, mood),

• in some studies – to prolong survival – but this remains controversial and has not yet been scientifically confirmed.

  
  

It is important to emphasize that mistletoe preparations are most often applied subcutaneously (under the skin), several times a week, and that the dosage is adjusted individually.

What does science say?

There are more than 100 clinical studies on fenugreek, but most of them come from German-speaking countries and some of them have methodological limitations (small groups, lack of placebo control).

Positive effects that have been replicated in multiple studies include:

• less fatigue during chemotherapy,

• reduced incidence of infections,

• improving the quality of life,

• in some patients – a subjective feeling of "resilience" or better functioning.

  
  

Important: Although some studies suggest a possible effect on survival, there is no solid scientific evidence to date that goat's milk thistle extends lifespan in any type of cancer.

Can it be combined with standard therapies?

In most cases - yes. Previous experience with chemotherapy, radiotherapy and immunotherapy shows no harmful interactions.

However, there are exceptions:

• patients with autoimmune diseases (e.g. multiple sclerosis, lupus),

• allergies to plants or preparations,

• pregnant and breastfeeding women – where there is insufficient data.

  
  

Because of the above, it is crucial to discuss the use of goat's rue with an oncologist - in order to assess the safety and justification in each individual case.

The position of professional societies

Major international oncology guidelines (ESMO, ASCO, NCCN) do not recommend the routine use of goat's milk, because there is not enough high-quality evidence of clinical benefit.

On the other hand, in some integrative oncology centers, especially in Germany and Switzerland, goat's milk thistle is part of standard supportive therapy, where it is used under strict medical supervision.

The position of professional societies

Goat's rue is not a "cure for cancer" - it cannot replace chemotherapy, immunotherapy, radiation or surgery . However, for some patients it can be a valuable addition: to alleviate the side effects of treatment, to enhance the subjective feeling of strength and quality of life, if there is professional guidance and the patient is well informed.

The decision to use it should be individual, informed and in consultation with your doctor. If you are considering goat's rue therapy, be sure to consult your oncologist. Not every preparation is the same, nor is every one suitable for everyone. In integrative oncology, the best results are achieved through collaboration – not by replacing conventional therapy.

Do you need more information on this topic? Contact us .

Literature:

• Tröger W, Galun D, Reif M, Schumann A, Stanković N, Milicević M. Viscum album [L.] extract therapy in patients with advanced pancreatic cancer: a randomized clinical trial on overall survival. Evidence-Based Complementary and Alternative Medicine. 2014;2014:593981. https://doi.org/10.1155/2014/593981

• Troger W, Jezic S, Zdrale Z, Tisma N, Hamre HJ. Quality of life and neutropenia in patients with early stage breast cancer: a prospective randomized study on the additional therapy with mistletoe extract. Breast Cancer: Basic and Clinical Research. 2009;3:35–45.

• Bar-Sela G, Wollner M, Hammer L, Agbarya A, Dudnik E, Haim N. Mistletoe as complementary treatment in patients with advanced non-small-cell lung cancer treated with carboplatin-based combinations: a randomized phase II study. Oncology. 2013;85(5):290–296. https://doi.org/10.1159/000354476

• Grossarth-Maticek R, Ziegler R. Prospective controlled cohort studies on long-term therapy of breast cancer patients with a mistletoe preparation (Iscador). Complementary Therapies in Medicine. 2006;14(2):76–84.

• Piao BK, Wang YX, Xie GR, et al. Impact of complementary mistletoe extract treatment on quality of life in breast, ovarian and non-small cell lung cancer patients: a prospective randomized controlled clinical trial. Anticancer Research. 2004;24(1):303–309.