Usually, general anesthesia in adults is provided by intravenous induction with propofol, which is the standard and most widely used technique. The availability of inhalation agents that are less irritating than halogenated ethers, less soluble and less toxic than halothane, have allowed since the end of the 1990s to reconsider the inhalation induction technique as an alternative to the intravenous route for the daily practice of adult anesthesia.The knowledge of the pharmacokinetics of the halogenated agent allows to predict the speed of sleep, to plan the administration of adjuvant anesthetic drugs such as morphinics, curares and nitrous oxide. For optimal use, despite its age, this technique nevertheless requires a minimum of training in the field.