There is quite a bit of confusion among the general public regarding what homeopathic remedies are. Even if a precise definition is given, there are some strong opinions expressed on both sides of the argument as to whether these remedies are actually working or if they are no more than fancy (and expensive) placebos. What does science have to say about this? Do homeopathic remedies actually work? Let's try to find out!
What is a homeopathic remedy?
Contrary to common belief, homeopathic remedies are not necessarily herbal remedies (some of which, like aspirin, originally extracted from willow tree bark, are legitimate drugs). Homeopathy is a field started by German physician Samuel Hahneman in 1796, based upon the belief that the dilution of a substance with alcohol or distilled water followed by vigorous shaking against an elastic body activates the vital energy of the diluted substance.
In effect, a homeopathic remedy consists of the extreme serial dilution of an active compound (1/1,000,000,000,000 and less), to the point that there is not a single molecule of the active compound left in the final pill or bottle. Homeopaths believe that the more diluted the solution, the more "potent" it is and therefore the most dilute substances are thought to be the strongest and deepest-acting. This is said to work because water has "memory", which is a bit worrying since if water manages to remember incredibly minute traces of long-gone chemicals, how about all the feces that it had in it last week before it passed through the water treatment plant and came back to our taps?
Richard Dawkins explaining the principle behind homeopathy
Does homeopathy work? Where is the evidence?
A number of systematic reviews have been published in very serious peer-reviewed journals (some of which are available here or here), have tested homeopathic remedies against medicines and, time and again, the former have been shown to trigger no added improvement on a number of conditions when compared with placebos, while regular medicine has consistently been shown to alleviate symptoms and speed up recovery.
While the scientific evidence is as solid as can be, you are quite likely to encounter people who are quite adamant that homeopathy works for them or for their loved ones. The key is how our brains perceive things and how the closer and more personal the experience, the more credibility our brain ascribes to it, regardless of the amount of real evidence.
First, the placebo effect is real. In other words, if our brain is convinced that a remedy will work, it will either enhance the action of a real remedy, or trigger an improvement in the condition even if the remedy is devoid of any real effect.
Explanation on the placebo effect
Additionally, perception bias occurs because of the timing of the intake of a remedy. If we consider the period from the start of the symptoms until total remission, the discomfort level tends to follow the shape of a bell curve. We are a lot more likely to try "weird" remedies when the symptoms are at their worst and this usually coincides with the start of the remission, with or without treatment.
Symptom severity through time
Therefore, due to this timing, we are likely to ascribe our remission to the remedy that was tried just before we got better. Moreover, the "weirder" the remedy, the more impact it will have on our memory and therefore, upon recalling our disease, we are more likely to remember the strange potion we took than the few tabs of the ubiquitous aspirin that we took simultaneously. This also works for others; if a loved one seems to have recovered due to some weird remedy, our brain will associate a strong positive emotion with that remedy, especially if it was administered by us!
Now, real science is always open to new ideas and, should any evidence in favor of homeopathy ever be obtained in properly controlled conditions, homeopathy would cease to be an "alternative" medicine and just become... medicine! If that were the case, it would totally revolutionize our most basic understanding of Physics. This would surely be worth a Nobel Prize at the very least, wouldn't it? So where are the candidates?
Richard Dawkins investigates homeopathy