http://en.wikipedia.org/wiki/Homeopathy
Law of similarsHahnemann observed from his experiments with cinchona bark, used as a treatment for malaria, that the effects he experienced from ingesting the bark were similar to the symptoms of malaria. He therefore decided that cure proceeds through similarity, and that treatments must be able to produce symptoms in healthy individuals similar to those of the disease being treated.[38] Through further experiments with other substances, Hahnemann conceived of the law of similars, otherwise known as "let like be cured by like" (Latin: similia similibus curentur)[39][40] as a fundamental healing principle. He believed that by using drugs to induce symptoms, the artificial symptoms would stimulate the vital force, causing it to neutralise and expel the original disease and that this artificial disturbance would naturally subside when the dosing ceased.[38] It is based on the belief that a substance that in large doses will produce symptoms of a specific disease will, in extremely small doses, cure it.
Hahnemann's law of similars is an ipse dixit axiom,[8] in other words an unproven assertion made by Hahnemann, and not a true law of nature.[9]