Perioperative fasting aims at decreasing the incidence of gastric content inhalation during anesthesia. Current knowledge concerning gastric emptying and the epidemiology of pulmonary aspiration authorizes new perioperative fasting guidelines. If prolonged fasting does not guarantee gastric emptiness at the induction of anesthesia, shortening preoperative fasting by allowing clear fluids two hours before surgery does not modify gastric content and does not increase the risk of gastric content aspiration, while enhancing the patient comfort by reduction of the fasting period. On the other hand, after surgery, the mandatory intake of water significantly increases the incidence of postoperative vomiting. Therefore new guidelines may be applied for children operated in ambulatory surgery settings: 1) clear fluids may be allowed until 2-3 hours before operation, 10 ml.kg-1, or even ad libitum for some authors (by clear fluids one means water, tea, coffee, apple juice, syrup with water); 2) drinking is not absolutely necessary before discharge from day care surgery unit and should be left to the child's own assessment.