How were the sick of the Hôtel-Dieu de Paris fed in modern times? What role did food play in their care? Where and how did the Hôtel-Dieu get supplies? What were its means? These are the principal questions that this thesis attempts to answer, using the deliberations of the Bureau and, when they still exist, the accounts (income and expenditure) of the Hôtel-Dieu. Mainly consisting of bread, meat and wine, but also broths for the seriously ill persons, the portions given to patients are copious, for the patient to the Hôtel-Dieu must be treated well and a good diet is the first treatment. The essentials do not include vegetables and fruits. It is difficult to know which amount of the latter was consumed. In times of scarcity (war, disaster, famine) the portions of bread, meat and wine are adjusted to the possibilities of supplying. The Hôtel-Dieu is making every effort to ensure its supplying, first relying on its farms and vineyards, then increasingly on the market. If a proper diet is the guarantee of a good health, the doctors at the Hôtel-Dieu waited until the eve of the French Revolution to consider that their prescriptions were to cover not only medicines but also diet. This little "revolution" did not occur without causing the reaction of nuns accustomed to controlling the patients’ diet.