Contrary to popular belief, 'homeopathy' is not the same as herbal medicine.
Homeopathy is based on three central tenets, unchanged since their invention by Samuel Hahnemann in 1796.
The law of similars states that whatever would cause your symptoms, will also cure those same symptoms. Thus, if you find yourself unable to sleep, taking caffeine will help; streaming eyes due to hayfever can be treated with onions, and so on. This so-called law was based upon nothing other than Hahnemann's own imagination. You don't need to have a medical degree to see the flawed reasoning in taking caffeine - a stimulant - to help you sleep; yet caffeine is, even today, prescribed by homeopaths (under the name 'coffea') as a treatment for insomnia.
Following on from his 'law of similars', Hahnemann proposed he could improve the effect of his 'like-cures-like treatments' by repeatedly diluting them in water. The more dilute the remedy, Hahnemann decided, the stronger it will become. Thus was born his 'Law of Infinitesimals'.
Taking a single drop of caffeine and diluting in ninety-nine drops of water creates what is known to homeopaths as one 'centesimal'. One drop of this centesimal added to another ninety-nine drops of water produces a two-centesimal, written as 2C. This 2C caffeine potion is 99.99% water and just 0.01% caffeine. At 3C the dilution is 0.0001% caffeine, at 4C it's 0.000001% caffeine, and so on. Homeopathic remedies are commonly sold at 6C (0.000 000 000 1%) and even 30C (0.000 000 000 000 000 000 000 000 000 000 000 000 000 000 000 000 000 000 000 1%) dilutions, which homeopaths will often drip onto little balls of sugar to sell.
When these numbers are written out, it's easy to see how absurd they are. At 12C you pass what is known as the Avogadro Limit, the point at which there is likely nothing of your original substance left.
By the time you reach 30C, you have more chance of winning the lottery five weeks running than you have of finding a single caffeine molecule in your homeopathic sleeping draft. It's just ordinary water, dripped onto ordinary sugar.
While transporting his remedies on a horse-drawn carriage, Hahnemann made another 'breakthrough'. He decided that the vigorous shaking of a homeopathic remedy would further increase its potency. This shaking process was named 'succussion'. When ritually preparing a homeopathic remedy, the homeopath will shake or tap the preparation at each stage of dilution, in order to 'potentize' it.
Modern homeopaths believe that this 'potentization' process allows the water to retain the 'memory' or 'vibrations' of the original substance, long after it has been diluted away to nothing. Of course, there is no good scientific evidence to suggest that water has such an ability, nor any indication of how it might be able to use this 'memory' to cure a sick patient.
Despite being rooted in supersition, ritual and sympathetic magick, the laws devised by Hahnemann are still in use by homeopaths today.
For Hahnemann's Laws to be correct, we would have to toss out practically everything we have learned over the past two centuries about biology, pharmacology, mathematics, chemistry and physics. Illnesses are not effectively treated by administering substances which cause similar symptoms; serial dilution and succussion does not 'potentize' a remedy. Water has no memory, nor any way of using one if it did! Homeopathy could never work in the way Hahnemann described it, but does it work at all?
The most comprehensive review of homeopathic treatments ever conducted was published in the medical journal The Lancet in 2005. The paper analysed every clinical investigation then published into the effects of homeopathy, and concluded that any apparent benefits from homeopathic 'treatments' were simply placebo effects. Homeopathy does not work. This conclusion was supported by the Cochrane Collaboration, an independent global network of medical professionals tasked with examining medical research to determine exactly which treatments are effective.