“Homeopathy works!â€? – is the watchword in the Faculty's argument for the acceptance of homeopathy by the medical profession, and its provision in the National Health Service. And it is true. The therapeutic method of homeopathy consistently achieves excellent results in clinical outcome studies2; health gains that exceed conventional expectations to an extent that patients sometimes reasonably describe them as ‘miraculous’. But despite evidence of the activity of high dilutions in general3, 4, 5 and 6 and homeopathic medicines in particular,7, 8, 9, 10 and 11 which only plausibility bias,12 a degree of intellectual dishonesty, or wilful ignorance can deny, we have to admit that the homeopathic therapeutic process is a ‘black box’.13 Which is true, of course, of all therapeutic methods.14 That is to say, many factors contribute to the effectiveness of the whole process, of which the efficacy of the specific intervention, in this case the homeopathic medicine, is only one. And in clinical practice we can never know for sure how much each element of the black box contributes to the outcome in any individual patient.