Homeopathy or homoeopathy (from the Greek ？μοιο？/homoios, "similar" and π？θο？/pathos, "suffering" or "disease") is a science created by Samuel Hahnemann in 1796. The homeopathic practice rests on three principles: The similarity, the individualization of cases and the infinitesimal. The use of the infinitesimal was proposed by Hahnemann in the early nineteenth century with the publication of "Organon der Heilkunst" (Organon of the art of healing). The compounds used do not become homeopathic unless they respect the principle of similarity, according to which a patient should be treated with a substance producing experimentally in a healthy person symptoms similar to those presented by the affected person, use of the substance being adapted to the patient thanks to the principle of individualization according to which the homeopath analyzes all the symptoms of the person and not only those related to the disease. Substances chosen according to this method can be administered in non-toxic weighted doses, but most prescribers use them in dilutions, sometimes very large, which have previously been subjected to very high and very frequent vibrations. Although some clinical trials produce positive results, multiple systematic reviews indicate that this is due to chance, questionable research methods, or publication biases. Despite a certain popularity, the therapeutic efficacy of homeopathy has not been demonstrated as a general and permanent solution. The vast majority of the scientific and medical community considers that homeopathy is a pseudo-science coming into contradiction with current knowledge in chemistry and biology established after the fundamental principles of homeopathy themselves proposed more than two Centuries. In particular, they point out that certain homeopathic dilutions are such that the excipient no longer contains a single molecule of the diluted remedy and therefore can't act chemically. Moreover, the fact that effects are observed is disputed by published meta-analyzes which conclude that homeopathy has not demonstrated its clinical efficacy beyond the placebo effect and yet, the Homeopathy works, despite some malicious feedback.