Some time ago, when we published our systematic review about the adverse effects associated with homeopathic remedies, there was an outcry of critics stating that it is not rational to claim, on the one hand, that homeopathic remedies are so dilute that they contain nothing and therefore do nothing and, on the other hand, that homeopathic remedies can cause side-effects. These people should, of course, have known better, but I admit it can be a little confusing. So, let me explain.
Every homeopathic remedy starts as a ‘mother tincture’. That is the undiluted stock prepared according to a homeopathic pharmacopoeia. The mother tincture is then diluted and shaken to give the first ‘potency’. Depending on the potency scale, this could be a ‘C1’ (1:100) or ‘D1’ (1:10). The resulting potency can be potentised again to give the second potency which can be potentised again to give the third potency. And this process of ‘serial dilution’ can be continued ad infinitum (the most common potency is the C30 which is a dilution of 30 times 1 : 100).
All of these remedies are by definition homeopathic, of course; even a mother tincture is strictly speaking a homeopathic remedy.
Now imagine we have a highly toxic stock, for instance, arsenic. This is by no means an extreme example, as many substances used in homeopathy are poisonous. A ‘D1’ of arsenic is both effective and dangerous: it is effective for killing rats and other unwanted creatures, and it is dangerous should a patient take it.
So, now we understand better why homeopathic remedies can, contrary to a common myth, cause direct adverse effects (in addition to the scenario outlined above, they can also be contaminated or adulterated, of course). We also realise that the ‘experts’ who protested against our review of side-effects of homeopathic remedies were either ignorant or stupid or both. Most importantly, we understand, I hope, that when we speak or write about the ineffectiveness of homeopathic remedies, we of course mean those that are too dilute to have any effect at all – and these are certainly the vast majority.