Homeopaths believe that a medicine, which causes a particular symptom in a healthy volunteer, will cure a similar symptom in a sick patient. From this phenomenon, it is possible to deduce a hypothesis: homeopaths should be able to distinguish a homeopathic medicine from a placebo by taking both and observing their effects. If true, this would support an effect of homeopathic medicines different from that of placebo. If false, it casts serious doubt on the contemporary homeopathic knowledge base and on homeopathic pathogenetic trials (HPTs) as currently practised. The study design was a double-blinded, crossover trial. It consisted of a 1-week study medication period, a 2-week washout period and a further 1-week on study medication. Bryonia in a 12c potency was chosen as the trial medication. Participants were recruited in the UK from the Faculty of Homeopathy and the Society of Homeopaths and were currently healthy, aged 18 or over with at least three years' clinical experience of homeopathy. Of the 500 recruitment packs despatched, we received 88 responses (17.6%). Seventy homeopaths were randomised of whom 50 completed the trial. In the main analysis 60% correctly identified the bottle containing Bryonia (n=40; 95% confidence interval 43%, 75%; P=0.27). There was evidence of an order effect: subjects were much more likely to think they received active Bryonia in the first rather than the second period. In this study a promising trend was observed that symptoms reported by some homeopaths may not be completely attributable to placebo. A multi-national, large-scale trial will be required to investigate this phenomena with adequate statistical power.

Can homeopaths detect homeopathic medicines? A pilot study for a randomised, double-blind, placebo controlled investigation of the proving hypothesis