Sir, I write in regard to Homeopathy and its ethical use in dentistry (BDJ 2011; 210: 299–301). Any ethical practice involving homeopathy must necessarily begin by telling the patient that it is scientifically implausible; for homeopathy to be valid most of what we know about chemistry and physics would have to be not just wrong but spectacularly wrong. Unfortunately this would undermine the placebo effect and the counselling nature of the consultation.1

Science has advanced in the last 200 years in a way that homeopathy simply has not; indeed, one (possibly the most) prominent homeopath, George Vithoulkas, has chided homeopaths for failing to follow the letter of Hahnemann's 'Organon'. In a comment on the Nature blogs, Vithoulkas says: 'to tear down a therapeutic system by examining and evaluating its theory instead of its therapeutic results is quite inappropriate. Until a few years ago, we did not know how aspirin works, yet it was the most frequently prescribed drug in conventional medicine.'

The point not noticed by Vithoulkas or made in the article is this: with drugs, no principles of science are violated; while the mechanism may be unknown in detail, it is plausible and consistent with other branches of knowledge, so the hierarchy of evidence may safely place clinical trials at the apex because the basic premises on which the proposed intervention are based are widely understood and accepted, the evidence gap is small and specific. With homeopathy the gap is substantial.

Disease is not caused by 'miasms' as Hahnemann believed and the basic principles of homeopathy, 'the law of similia', 'potentization' and 'the law of infinitesimals' are articles of faith, not laws of nature. There is no credible evidence that any one of them is a valid generalisable principle. Are we really to believe that powerful healing can result from forces unmeasurable by any scientific instrument?

In order to be persuasive we therefore need evidence massively more compelling than the studies cited, because we'd have to discard everything we have learned about physics and physical chemistry since Avogadro. As it turns out, systematic reviews of the research show that the more positive results are from methodogically weaker studies, while stronger methodology tends inexorably toward the conclusion of placebo plus experimenter bias.2,3,4,5

As the House of Commons Science and Technology Committee concluded, there is no robust evidence that homeopathy is effective beyond placebo.6 To pretend otherwise is unethical as it violates the principle of informed consent. In a world where it is seriously being promoted for the treatment of cancer and radiation poisoning, and the prevention of malaria and typhoid, with provably devastating results, I am afraid your publication of this article is cause for serious concern.