Potentisation is a process by which a given substance is repeatedly diluted and succussed (shaken vigorously) according to procedures defined in the European Pharmacopoeia. The final dilution factor may be so high that no traces of the potentized substance can be measured anymore by analytical methods. It is therefore sometimes argued that homeopathic therapy is a placebo treatment.
Basic research in homeopathy mainly investigates whether potentization generates pharmaceutical preparations with specific effects or not. The current state of basic research in homeopathy is summarized below. In short, the outcome of most bioassays is not compatible with the placebo hypothesis: in a large number of investigations, homeopathic preparations exerted specific effects different from placebo, when applied in adequate experimental settings. Also in physicochemical research, empirical evidence for specific physicochemical properties was observed.
Clinical research in homeopathy uses nonrandomized studies (NRS) to assess real-world effectiveness in daily practice, safety, and randomized controlled trials (RCT) to investigate specific remedy effects (efficacy) under controlled conditions. Furthermore, homeopathic drug provings are conducted, and a large number of single case studies is available. The current state of clinical research is summarized below. In short, the most recent meta-analyses of RCTs across all indications concluded that there is evidence for specific effects of homeopathic remedies superior to placebo when prescribed by a qualified homeopath. Furthermore, there are several meta-analyses on specific indications (e.g. allergic complaints, childhood diarrhoea) which provide evidence for specific effects of homeopathic preparations superior to placebo.
Synthesizing the current state of preclinical and clinical research, it can be concluded that there is empirical evidence that homeopathic preparations exert specific effects superior to placebo when adequately applied (i.e. by qualified prescription in clinical settings, and in adapted preclinical experimental set-ups).
These preclinical and clinical research results call for intensified research into the still unknown mode of action of homeopathic preparations, on the pharmaceutical as well as on the biomedical level.
