Homeopathy is a system of medicine based on the similia (‘treating like with like’) principle. It usually entails taking highly diluted remedies by mouth. Homeopaths claim to treat the individual patient holistically such that the body is stimulated to heal itself. Homeopathy is thus advocated for all human conditions; in oncology this is mostly for palliative and supportive care.
A systematic review of eight controlled clinical trials of homeopathy for the prevention or treatment of adverse effects of cancer treatments concluded that the evidence is not convincing. More recent trials fail to demonstrate that homeopathy is an effective therapy for cancer.
There are no serious direct risks associated with homeopathy but there are indirect risks, if homeopathic preparations are used in place of conventional cancer treatment.
Last updated and revised in July 2016 by Karen Pilkington.
Updated in May 2013 by Edzard Ernst.
Updated and revised in November 2011 by Edzard Ernst.
First published in June 2010, authored by Edzard Ernst.
Karen Pilkington, Edzard Ernst, CAM-Cancer Consortium. Homeopathy [online document], http://cam-cancer.org/en/homeopathy-0. July 12, 2016.
Description and name
Homeopathy (or homoeopathy) is a system of medicine based on the similia (‘treating like with like’) principle. It usually entails taking highly diluted remedies by mouth.
Homeopathic remedies are frequently made from natural substances, e.g. plants or minerals, but in principle they can originate from any material (e.g. Berlin Wall remedy) or even non-material sources (e.g. X-ray remedy).
Application and dosage
Homeopathy is defined as “a therapeutic method using preparations of substances whose effects when administered to healthy subjects correspond to the manifestation of the disorder in the individual patient”1. In other words it is based on the similia principle which states that “substances may be used to treat disorders whose manifestations are similar to those which they will themselves induce in a healthy subject (Similia similibus curentur = ‘let like be cured by like’)1.
Homeopathic preparations are produced through a process of serial dilution and succussion/shaking (potentisation) of the “mother tincture”. Preparations are available in a range of dilutions, from low dilutions where concentrations of the original substance are measurable, to extremely high dilutions in which it is unlikely that a single molecule of the original substance remains. Homeopathic potencies are designated by a number and a letter. The number refers to the number of successive serial dilutions to which the starting material has been subjected. The letter refers to the scale used, the decimal (D or X) and centesimal scales (C) being those most widely used. In the decimal method a 1 in 10 dilution is used at each stage while in the centesimal method a 1 in 100 dilution is used in successive stages1.
Homeopathic remedies are usually prescribed on a highly individualized basis; ideally, the totality of the patient’s complaints should match the “drug picture” of the remedy which has been defined in so-called “provings”, i.e. homeopathic pathogenetic trials. These are studies which test a substance at a non-toxic level on healthy volunteers to determine the symptoms it provokes and which, according to the similarity principle, it may be used to treat2.
Today, there are several variations of homeopathy as described above e.g. isopathy (homeopathically diluted remedies derived from the causative agent of the disease itself), or homotoxicology (illness is understood as the body’s inability to effectively cope with its burden of toxins), or complex homeopathy (combination of two or more homeopathic medicines in a standardised mixture), or clinical homeopathy (one or more single remedies for standard clinical situations)1.
Homeopathy was developed by the German doctor Samuel Hahnemann (1755-1843) and became popular, first in Europe, then also in a wide variety of countries around the world, especially in the US, India and South America. When more and more effective pharmacological treatments were discovered, the popularity decreased. Recently, it has experienced somewhat of a renaissance in parallel with the growing interest in CAM.
Today homeopathy is practised both by doctors, other health professionals and by lay homeopaths (or “professional homeopaths”). The former two groups are statutorily regulated by their professional bodies, while the latter are often not regulated. In the UK, for example, anyone regardless of background can currently practise as a homeopath. Homeopathic preparations can be prescribed by a homeopath during a consultation but can also be purchased from health food shops, some pharmacies or online suppliers.
Claims of efficacy
Homeopaths believe that homeopathic remedies stimulate the body’s own healing powers (vis medicatrix naturae), i.e. the inherent ability of an organism to overcome disease and disorder and regain its health1. Therefore, Hahnemann viewed homeopathy as a “cure all”2. Today it is mostly advocated as a treatment or prevention of chronic conditions and often administered as an adjunctive treatment3.
Mechanism of action
No biologically plausible mechanism of action is known. A 2007 systematic review of in-vitro research on high potency effects found that “no positive result was stable enough to be reproduced by all investigators”; however, it also stated that “even experiments with high methodological standard could demonstrate an effect of high potencies”4. The fact that homeopathic preparations “may exhibit specific physiochemical properties”5 does not mean that a mechanism of action has been identified. Several recent pre-clinical investigations have suggested direct anti-cancer effects of homeopathic preparations on tumour cells, such as apoptosis and stimulation of natural kille cell activity6,7. However, these findings require independent replications.
In oncology, homeopathy is mostly but not exclusively used as palliative and supportive care to improve quality of life, to ease or prevent the adverse effects of treatments, or to alleviate or prevent the symptoms of the cancer.
Prevalence of use
This depends crucially on the country and the setting. For instance, homeopathy is popular in France8, Italy9 and Germany10. Some European centres are specialized and use homeopathy for the majority of cancer patients. Elsewhere, it would not usually be used at all or only very rarely. Data from the Netherlands indicate that 19% of all cancer patients used homeopathy11. A survey of oncology patients in Italy indicated 6.4% used homeopathy12. Prevalence appears to vary by type of cancer, for example, surveys across a range of European countries suggested higher rates of use in breast cancer (16-24%) compared with gynaecological cancers (<5%)13,14.
Non-doctor homeopaths are in many countries not regulated by statute. In some countries, they are not officially allowed to practise but usually this regulation is not enforced. In some countries, for example the UK, it is illegal for homeopaths to claim they can cure cancer.
Costs and expenditure
Homeopathic remedies tend to be relatively inexpensive. A first consultation with a homeopath can last one hour or longer and can cost between £30 to £120 per session or €120-€180, follow-up sessions are shorter and therefore less costly. In Germany, some health insurers reimburse consultations with homeopathic physicians15.
A systematic review of systematic reviews of homeopathy conducted in 2002 concluded that there is no evidence from systematic reviews that homeopathy is effective beyond placebo for any condition16. A 2009 Cochrane review was aimed at evaluating “the effectiveness and safety of homeopathic medicines used to prevent or treat adverse effects of cancer treatments"17. The authors found eight controlled clinical trials: three studied adverse effects of radiotherapy, three studied the adverse effects of chemotherapy and two investigated menopausal symptoms due to breast cancer therapy. One rigorous study of Calendula extract ointment (n=254) suggested benefit for the prevention of radiotherapy-induced dermatitis compared to controls treated with trolamine18. Another small (n=32) yet rigorous study found that Traumeel S mouthwash (a complex homeopathic remedy) was better than placebo for chemotherapy-induced stomatitis19. The other trials were either methodologically weak or had negative results. Neither of the two positive studies employed high dilutions; thus their effects might be explicable through the pharmacological properties of their ingredients.
In 2012, Sencer et al published a multi-center, double-blind, randomized trial comparing Traumeel with placebo in paediatric cancer patients suffering from mucositis20. Traumeel or placebo were applied a five-time daily as a mouth rinse. The efficacy of the treatments was assessed using the modified Walsh scale for mucositis, scored daily from Day -1 to 20 days. The main outcome was the sum of Walsh scale scores over this period. Other outcomes included narcotic use, days of total parenteral feeding, days of nasogastric feeding and adverse events. In 181 evaluable patients, there was no significant inter-group difference in any outcome measure.
These findings seem to tie in with those from a recent non-randomised, controlled clinical trial with patients suffering from radiation-induced mucositis. The participants were 20 patients who were receiving radiotherapy or radiochemotherapy for head and neck tumours. Five times per day during the observational period, participants self-administered daily mouth rinses with either sage tea (Salvia officinalis, control group) or Traumeel S solution (intervention group). Two independent physicians determined the grade of oral mucositis at least once per week, and the research team derived the degree of oral pain from diaries that participants kept. Both groups were comparable in terms of tumour and treatment characteristics. The research team could not confirm any appreciable specific effect of Traumeel S on the primary endpoints21.
Perol et al published a randomized, placebo-controlled trial to evaluate the efficacy of a complex homeopathic medicine, Cocculine ( main homeopathic ingredient = nux vomica), in the control of CINV in non-metastatic breast cancer patients treated by standard chemotherapy regimens22. The primary endpoint was nausea score measured after the 1st chemotherapy course using the FLIE questionnaire (Functional Living Index for Emesis) with 5-day recall. Secondary endpoints were: vomiting measured by the FLIE score, nausea and vomiting measured by patient self-evaluation (EVA) and investigator recording (NCI-CTC AE V3.0) and treatment compliance. In total, 431 patients were randomized: 214 to Cocculine (C) and 217 to placebo (P).There was no difference between the 2 arms when primary endpoint analysis was performed by chemotherapy stratum; or in the subgroup of patients with susceptibility to nausea and vomiting before inclusion. In addition, nausea, vomiting and global emesis FLIE scores were not statistically different at any time between the two study arms.
The most recent trial was a pragmatic RCT in which 410 patients with various types of cancer were randomised to receive classical homeopathy in addition to standard anti-cancer treatment or standard treatment alone23. Homeopathy treatment was individually tailored to each patient. The main outcome measures were global health status and subjective wellbeing. Improvements in both were recorded in the homeopathy group based on questionnaires completed at baseline and the two follow-up visits at intervals of two months. At least one outcome measurement was obtained for 373 patients. The improvement in global health status between visits 1 and 3 was significantly greater in the homeopathy group by 7.7 (95%CI 2.3—13.0, p = 0.005) when compared with the control group. A significant difference was also reported for subjective wellbeing (14.7 95% CI 8.5—21.0, p < 0.001. A significant improvement in subjective was seen in the control patients between the first and third visits. This was a well-designed, rigorous study with adequate randomisation and allocation concealment, and procedures for dealing with missing data. However, the lack of a control intervention and consequent lack of blinding combined with patient-reported subjective outcome measures, mean that the risk of bias is high.
A 2011 prospective cohort study compared cancer patients who had opted for homeopathic treatments as an adjunct to conventional cancer therapies with patients who had chosen to have onventional care only24. Matched pairs were formed of patients with the same cancer type and prognosis. Encouraging effects in terms of fatigue and quality of life were noted after three months. It is unclear, however, whether the outcome was a result of the treatment or due to selection bias as this was an observational study.
Highly diluted remedies are unlikely to cause serious adverse effects. Less dilute remedies, that may still be described as ‘homeopathic’, are likely to have a pharmacologic effect of the main active ingredient.
The most serious risk of homeopathy is indirect: if homeopathic remedies replace conventional cancer treatment, this can cause adverse outcomes including premature deaths. In this context, it is important to realise that, according to one German survey24, cancer patients seek homeopathic treatments much more frequently from providers who are not physicians than from physicians.
Do not use as a replacement for conventional cancer treatment.
- Swayne J. International dictionary of homeopathy. Churchill Livingstone, Edinburgh. 2000.
- Ernst E. The heresy of homoeopathy. Br Homeopath J 1998; 87: 28-32.
- Spence DS, Thompson EA, Barron SJ. Homeopathic treatment for chronic disease: a 6-year, university-hospital outpatient observational study. J Altern Complement Med 2005; 11: 793-798.
- Witt CM, Bluth M, Albreacht H et al. The in vitro evidence for an effect of high homeopathic potencies. A systematic review of the literature. Complement Ther Med 2007; 15(2): 128-138.
- Baumgartner S, Wolf M, Skrabal P et al. High-field 1HT1 and T2 NMR relaxation time measurements of H2O in homeopathic preparations of quartz, sulfur, and copper sulfate. Naturwissenschaften 2009; 96: 1079-1089.
- Preethi K, Ellanghiyil S, Kuttan G et al. Induction of apoptosis of tumor cells by some potentiated homeopathic drugs: implications on mechanism of action. Integr Cancer Ther 2012; 11: 172-82.
- Toliopoulos IK, Simos Y, Bougiouklis D et al. Stimulation of natural killer cells by homoeopathic complexes: An in vitro and in vivo pilot study in advanced cancer patients. Cell Biochem Funct 2013; doi: 10.1002/cbf.2960.
- Thomas-Schoemann A, Alexandre J, Mongaret C et al. Use of antioxidant and other complementary medicine by patients treated by antitumor chemotherapy: a prospective study. [in French]. Bull Cancer 2011; 98(6): 645-653.
- Clerici CA, Veneroni L, Giacon B et al. Complementary and alternative medical therapies used by children with cancer treated at an Italian pediatric oncology unit. Pediatr Blood Cancer 2009; 53(4): 599-604.
- Längler A, Spix C, Edelhauser F et al. Use of homeopathy in pediatric oncology in Germany. Evid Based Complement Alternat Med 2011; 2011: 867151.
- Singendonk M, Kaspers GJ, Naafs-Wilstra M et al. High prevalence of complementary and alternative medicine use in the Dutch pediatric oncology population: a multicenter survey. Eur J Pediatr 2013; 172: 31-7.
- Bonacchi, A., L. Fazzi, A. Toccafondi, M. Cantore, A. Mambrini, M. G. Muraca, G. Banchelli, M. Panella, F. Focardi, R. Calosi, F. Di Costanzo, M. Rosselli and G. Miccinesi. Use and perceived benefits of complementary therapies by cancer patients receiving conventional treatment in Italy. J Pain Symptom Manage 2014 47(1): 26-34.
- Molassiotis A, Scott JA, Kearney N et al. Complementary and alternative medicine use in breast cancer patients in Europe. Support Care Cancer 2006;14:260-7.
- Molassiotis A, Browall M, Milovics L et al. Complementary and alternative medicine use in patients with gynecological cancers in Europe. Int J Gynecol Cancer 2006;16 Suppl 1:219-24.
- Deutscher Zentralverein Homöopathischer Ärzte. Homöopathie und Kostenerstattung. Available online, accessed 12 July 2016.
- Ernst E. A systematic review of systematic reviews of homeopathy. Br J Clin Pharmacol 2002;54:577-582.
- Kassab S, Cummings M, Berkovitz S et al. Homeopathic medicines for adverse effects of cancer treatments. Cochrane Database of Syst Rev 2009;2:CD004845.
- Pommier P, Gomez F, Sunyach MP et al. Phase III randomized trial of Calendula officinalis compared with trolamine for the prevention of acute dermatitis during irradiation for breast cancer. J Clin Oncol 2004;22:1447-53.
- Oberbaum M, Yaniv I, Ben-Gal Y et al. A randomized, controlled clinical trial of the homeopathic medication TRAUMEEL S® in the treatment of chemotherapy-induced stomatitis in children undergoing stem cell transplantation. Cancer 2001;92:684-90
- Sencer SF, Zhou T, Freedman LS et al. Traumeel S in preventing and treating mucositis in young patients undergoing SCT: a report of the Children's Oncology Group. Bone Marrow Transplant 2012;47:1409-11.
- Steinmann D, Eilers V, Beynenson D et al. Effect of Traumeel S on pain and discomfort in radiation-induced oral mucositis: a preliminary observational study. Altern Ther Health Med 2012;18:12-8.
- Pérol D, Provençal J, Hardy-Bessard AC et al. Can treatment with Cocculine improve the control of chemotherapy-induced emesis in early breast cancer patients? A randomized, multi-centered, double-blind, placebo-controlled Phase III trial. BMC Cancer 2012;12:603.
- Frass M, Friehs H, Thallinger C et al. Influence of adjunctive classical homeopathy on global health status and subjective wellbeing in cancer patients - A pragmatic randomized controlled trial. Complement Ther Med 2015;23:309-17.
- Rostock M, Naumann J, Guethlin C et al. Classical homeopathy in the treatment of cancer patients--a prospective observational study of two independent cohorts. BMC Cancer 2011;11:19.