In early nineteenth century medicine, the concepts of organic evolution and natural selection emerged in different contexts, partly anticipating Darwinian revolution. In particular, the anatomical concept of disease favored the perception that men and animals were very similar from a morphological, physiological and pathological point of view, and that this could indicate a certain degree of kinship between them. The debate around human races and human pathological heredity saw first formulations of the principle of natural selection, even if without a full appraisal of its evolutionary implications. Charles Darwin took many inspirations from these medical theories. The impact of the theory of evolution formulated by him in 1859 was only apparently slight in medicine. It is even possible to support that evolutionary concepts contributed in a significant way to the most important medical issues, debates and new discipline in the period between 1880 and 1940.