Letters Homeopathy, a ‘‘helpful placebo’’; or an unethical intervention? Edzard Ernst Reply Paula Ross The Society of Homeopaths. 11 Brookfield, Duncan Close, Moulton Park, Northampton NN3 6WL, UK In the letter of 3 November 2009, Ezard Ernst claims that there are only two possible descriptions for homeopathy: it is either a ‘helpful placebo’ or an ‘unethical intervention’. In fact, neither of these descriptions is accurate. Ernst argues that because homeopathic medicines are at ultramolecular dilutions, they cannot have a specific effect. In fact, this only precludes a biochemical mode of action; in the 21st century with advances in biophysics it should not be too much of a stretch for any scientist to accept the possibility that a medicine might interact with the body energetically rather than chemically. Indeed, there is in vitro evidence to support such a hypothesis [1], and to demonstrate biological effects of ultra-high dilutions [2,3]. Ernst debates whether it is ethical for homeopaths to use a placebo if they know it is only a placebo. This debate is irrelevant; homeopaths know they are providing more than a placebo, both from their own clinical experience with babies and young children, and from the results of high- quality studies that took into account both regression to the mean and the placebo effect; 74 of 147 high-quality random- ised controlled trials (RCTs) comparing homeopathy with placebo or conventional treatment have been able to draw firm conclusions: 63 were positive for homeopathy and 11 were negative [Mathie, R. (2009) Clinical research evidence in favour of homeopathy. www.britishhomeopathic.org/ export/sites/bha_site/research/evidence-by-condition-refs. pdf]. Results of 63:11 in favour of a true clinical effect would usually support the conclusion that the intervention is efficacious and therefore ethical; what is unethical is to view results differently simply because it is homeopathy that is being examined. The number of RCTs is small, but these results, especially when considered in the context of the complete evidence base for homeopathy (Mathie, R. The research evidence base for homeopathy. (2008) www.britishhomeopathic. org/export/sites/bha_site/research/evidencesummary.pdf) justify further academic enquiry. Meanwhile the only ethical path is for homeopaths to continue to provide this ‘helpful and effective intervention’, particularly in cir- cumstances where patients have already exhausted all conventional treatment options. References 1 Montagnier, L. et al. (2009) Electromagnetic signals are produced by aqueous nanostructures derived from bacterial DNA sequences. Interdiscip. Sci. Comput. Life Sci. 1, 81–90 2 Witt, C.M., Bluth, M. and Albrecht, H. et al. (2007) The in vitro evidence for an effect of high homeopathic potencies – a systematic review of the literature. Complement. Ther. Med. 15, 128–138 3 Endler, P.C., Heckmann, C. and Lauppert, E. et al. (1998) The metamorphosis of amphibians and information of thyroxine. In Fundamental Research in Ultra High Dilution and Homoeopathy (Schulte, J. and Endler, P.C., eds), Kluwer Academic Publishers 0165-6147/$ – see front matter ß 2010 Published by Elsevier Ltd. doi:10.1016/j.tips.2010.04.006 Trends in Pharmacological Sciences 31 (2010) 297 Letters Response Trends in Pharmacological Sciences: invited response to letter by Paula Ross for TIPS Edzard Ernst Complementary Medicine Peninsula Medical School, 25 Victoria Park Road, Exeter, Devon EX2 4NT, England The letter by Paula Ross from the UK ‘Society of Homeo- paths’ essentially makes three points. It claims there is in vitro evidence for biological effects of ultrahigh dilutions of medication. A review of the relevant literature concluded that ‘no positive result was stable enough to be reproduced by all investigators’ [1]. Even if such effects existed, homeo- paths would still need to explain by exactly which mech- anisms they lead to improvements in human health. Ross also claims that homeopaths know from their experience that homeopathy is effective. We all know that clinical experience is important, but it is not a substitute for evidence. Experience of clinical benefit can be due to a range of factors unrelated to the treatment in question; for example, regression to the mean, natural history of the disease, and placebo effects, among others. Update Corresponding author: Ernst, E. (Edzard.Ernst@pms.ac.uk). 297