[The homeopathy problem in contemporary medicine].
The aim of this study is to explain homeopathy, and make a critical evaluation of the doctrine and its clinical practice. The discipline of homeopathy, a medical doctrine advanced by Samuel Hahnemann in the late eighteenth and the early nineteenth centuries, is based on a physiological theory according to which a "vital force dominates the human body in an unopposed and dynamic way"; disease processes are considered the consequence of a disturbance of this vital force. According to this doctrine, there are only three diseases: psora, sycosis and lues. Drugs are believed to act according to the principle of similitude, their efficacy increasing with their progressive dilution. Several schools of homeopathy have emerged since Hahnemann's death. Although they differ from each other, they share two of the fundamental principles advanced by the founder. Homeopathic clinical teaching aims at identifying the greatest number of signs present in the patient and then, on the basis of these signs, and irrespective of any diagnosis, the homeopathic specialist decides what drug(s) should be administered. Homeopathy is a doctrine that can be rationally criticized from three standpoints. First, its content contrasts radically with current scientific knowledge of chemistry, pharmacology, and pathology. Second, despite the fact that homeopathic specialists claim many therapeutic successes, the small number of rigorous studies conducted have not as yet provided convincing evidence that homeopathic treatment is effective against particular disease processes. Third, from a methodological standpoint, homeopathy has a number of serious flaws: above all, it violates both the principle of falsifiability enunciated by Karl Popper as a criterion for the demarcation between science and pseudo-science, and the principle of operative definition. Homeopathy cannot therefore be considered a scientific discipline.