Sir, there is an interesting and ongoing debate about the ethics of using placebos in medicine, so I was disappointed that the response to Unethical aspects of homeopathic dentistry1 has focused instead on disputing the overwhelming scientific consensus that homeopathy is baseless and unproven.2,3,4,5

It is well known that people are prone to trust experiences and evidence that support their preconceptions. It is therefore inappropriate to challenge such an established consensus in the letters and opinion pages, particularly by citing personal experiences, individual studies and one's own website. To make a convincing case, a large, unbiased systematic review is needed. The Cochrane Collaboration has already done this for several conditions,6,7,8,9,10 but has yet to find compelling evidence of any benefit. Usually, few or no well-conducted trials exist.

In the absence of evidence that homeopathy works, one is forced to estimate its priori plausibility as the homeopaths do – by comparing it to experience. The two founding principles of homeopathy are that a patient presenting with a given symptom is best cured by a substance known to cause that symptom, and that diluting medicine makes it stronger – including well beyond the point where no medicine remains. I wonder how your readers' clinical experiences compare to these principles.