An apparatus for administering an anesthetic agent for a subject breathing is disclosed herein. The apparatus includes a liquid reservoir (9) for an anesthetic agent and an anesthetic agent dosing unit (7) in fluid connection with the liquid reservoir (9) and which anesthetic agent dosing unit is connectable to an airway tube for delivering breathing gases to a subject, the dosing unit including a first member (27) to produce anesthetic agent droplets having a diameter less than 100 µm.
