The paper unravels the close connection that, from the end of the 17th century until well into the 19th century, brought together meteorologists and physicians into one common program. This connection was based upon the works of the Greek physician Hippocrates, and particularly “Airs, Waters and Places”. The ancient doctrine underwent a strong revival in the 18th century and formed the basis of the founding of the “Société Royale de Médecine” in Paris. This society, under the direct guidance of the French government, launched a nationwide medico-meteorological enquire. Its goal was to find the relationship between health, weather, climate and also the environment in order to understand the appearance and spread of illnesses, particularly the epidemics and epizootics. The meteorological observations carried out by the physicians in the framework of the neo-Hippocratic hypothesis form the cornerstones of the early meteorological observations in Belgium. Their importance in Global Change is highlighted because of their use in the climate reconstruction over the last hundreds of years.