Homeopathic arnica

In homeopathic proving studies, remedies are usually given to healthy individuals in 30C potency, twice a day, for one to two weeks. This usually triggers symptoms in susceptible individuals who ‘prove’. These symptoms are then recorded by the homeopath and historically have formed the basis of the homeopathic materia medicas. When a patient is unwell, ‘the remedy picture’ described in the materia medica is then matched to the patient's symptoms and the most appropriate remedy selected, hence the term ‘like cures like’. Stevinson et al.¹ gave a potency and posology of arnica that, according to basic homeopathic principles, would be very likely to trigger a proving reaction either during or a few days after the operation. I am not aware that any of the individuals involved in the study was a practising homeopath so this may well be an oversight. It does, however, make the study very difficult to interpret; is it a proving study of arnica, in which case one would have expected the groups undergoing treatment to be worse than the controls, or is it a therapeutic study of arnica, in which case why would the investigators choose a ‘proving dose’? This might represent a fundamental methodological flaw which could throw some doubt on the study's conclusions. Of course, the principles of homeopathic practice are unproven, but until we know whether they are correct or incorrect, we should certainly take note of them in studies designed to evaluate the effects of homeopathy.