Very recently, I've had an occasion to cross swords with a close friend, a working molecular biologist, whose inexplicable belief in homeopathy flabbergasted me. I do know that we Indians have a culturally-conditioned, deep and abiding faith in many modalities of quackery, including homeopathy which is very popular in India. Nevertheless, I'd have expected someone like my friend, who has delved deep into the inner workings of cells, to naturally outgrow such infantile belief systems. Clearly, I was mistaken - but more about that later.
This post is a brief (hopefully!) primer on homeopathic dilutions. Hahneman, the founder of homeopathy, believed that there is a 'spirit' responsible for different manifestations of life and termed it Vital Force (Aphorism 10 of Hahnemann's Organon of Medicine) - without which "The material organism ... is capable of no sensation, no function, no self preservation; it derives all sensations, and performs all functions of life solely by means of the immaterial being (the vital force) which animates the material organism in health and disease." In this form of primitive, atavistic belief system (for Hahnemann was no Jedi!), disease is caused when this mythical vital force is deranged, which leads to the abnormal sensations, signs and symptoms - together constituting the disease.
Hahnemann decided that the "medicine" required for proper healing must be used in the smallest of quantities. This small quantity was expected to produce least possible excitation of the vital force, while being sufficient to cause gentle, remedial changes to that force. Thus was born his Law of Minimum (a.k.a. Law of Infinitesimal; Aphorism 246), and this concept lead to the that of potentization, a process in which serial dilutions of the homeopathic remedy along with vigorous shaking (a.k.a. succussion) was expected to increase its efficacy or 'potency'.
In homeopathy, dilutions of 1:10 are designated by the Roman numeral X (1X = 1:10, 3X = 1:1,000, 6X = 1:1,000,000). This is the designation popular in amongst Indian homeopaths. Related to this, a factoid that emerged in course of the conversation with my friend is quite interesting (and the main inspiration behind this post): my friend was apparently under the impression that the 'X' designations used for homeopathic dilutions in India (such as 6X, 30X, 200X) referred to concentrations!
Now, I realize that this may easily be a common mis-perception for those of us that work at the bench, because there we often do refer to concentrations of stock solutions in terms of 'X' (higher X = more concentrated; e.g. 2X phosphate buffer, with double quantities of all components in a given volume; 5X NaCl, a five times concentrated saline solution; 6X Gel-loading buffer, and so forth). What I don't know is whether Indian homeopaths, knowing this, deliberately play up the X designations for their dilutions.
Semyon Nicolaevich Korsakov (1788-1853), a Russian landowner and clerk in the Ministry of Internal Affairs of that country, invented a quicker way of preparing high dilutions. In the Korsakov method of "potentization" (which Hahnemann approved in 1832), the container with the remedy is shaken ('succussed') and then just emptied and refilled, and the dilution factor is assumed to be 1:100 - one 'centesimal' or 'C' to the homeopath. This is the preferred dilution designation in many European country. So the first dilution produces 1C; second dilution of this 1C - done in the same way - is called 2C, where the original remedy is in effect diluted 1:10,000, or 1:(1002). In preparing Korsakov potencies, distilled water is used rather than alcohol (sometimes, only after the 30th dilution), which is cost effective when, for example, the dilution steps have to repeated 200 times, to get a dose of 200K (200 Korsakov dilutions; a.k.a. 200C or 200CK; "CK" stands for "centesimal Korsakovian). The resulting fluid is used to moisten small 5 mg globules (balls) of lactose, and sold as the remedy.
I'd like my readers to appreciate that going by the same rule, at 3C, the original substance is diluted 1:1,000,000 and is present at 0.0001%. At the commonly sold homeopathic dose of 6C, the dilution is 1:(1006), or 1:1012. Therefore, at 12C or 24X, what is known as the Avogadro's Limit is crossed, and the laws of chemistry and physics indicate it unlikely that a single molecule from the original substance will remain in the solution. Avogadro's Constant (approximated to 6.022 x 1023 mol-1) expresses the number of elementary entities per mole of substance. To illustrate, one mole of pure Sodium Chloride, the common salt, has a mass of 58.443g and contains ~6.022 x 1023 molecules; this much Sodium Chloride dissolved in 1 liter of water produces a 1 molar (1M) saline solution. If this solution is to be then diluted by the Korsakov method, at 12C the dilution would be 1:1024, and a single molecule of Sodium Chloride may not remain in it. Now consider that homeopathic remedies are often diluted to 30C or even 200C. I hope you can appreciate the absurdity of this proposition.
The so-called 'laws' of homeopathy devised by Samuel Hahnemann are rooted in superstition and pre-scientific magical beliefs about the human body, and are contradicted by our accumulated knowledge of past two centuries about biology, physiology, anatomy, pharmacology, physics and chemistry. The claims of homeopaths are not backed by any solid scientific evidence; homeopathic remedies, when tested under rigorous conditions, fail to work better than plain sugar pills.
The fact that people, anecdotally, still report feeling better after taking homeopathic remedies (better referred to as 'quack nostra') points to Placebo Effects, which are vague nonspecific effects of uncertain provenance, unrelated to the remedy being used. In many cases, homeopaths claim success in conditions that are essentially self-limiting. Oftentimes, unregulated, untested and potentially dangerous herbal products, containing some active principle (therefore, not technically homeopathic), also appear in the market under the sobriquet 'homeopathic product'. A recent example is that of Zicam, labeled 'homeopathic remedy', which caused permanent loss of smell (anosmia) in patients using it as a cold remedy, and was subsequently withdrawn from the market under pressure from the FDA. A nice summary of homeopathic modalities is at Quackwatch.
Homeopathy as a treatment modality is implausible, unproven despite a good number of studies, and unsurprisingly ineffective. Yet, homeopaths in many countries - with their flawed understanding of the disease process - continue to make claims about serious conditions that the placebo effect could not possibly treat or cure, such cancer, HIV infection, malaria, yellow fever, autism, tuberculosis, and so forth. Therefore, accepting homeopathy as a viable alternative to conventional medicine lends it undue legitimacy that has the potential of causing real harm.