As early as the beginnings of human life, man has been concerned with the protection of his health condition, consequently, of his life, an attitude best expressed by the maxim of Hippocrates (460-377 B.C.): It is easier to prevent a disease than to treat it. Hippocrates was the first to lay the basis of the epidemiological methodology, establishing patterns of populational inquiries on public health condition, elaborating anamnesis, observation, description, comparsion methods, thus succeeding in stating causal relations and prevention principles, largely applied in his books On air, waters and places and On epidemies. Hippocrates and his followers demonstrated that prevention of any disease involves knowledge and neutralization of the factors responsible for creating discrasia, along with promotion of those which assure eucrasia (homeostasis)