Inhalation induction is the use of anaesthetic gases and vapours to induce a state of surgical anaesthesia from a state of full consciousness.

Although it is routine to induce general anaesthesia by the intravenous (IV) route, the inhalational route remains preferable in certain circumstances.

A patient undergoing an inhalation induction will exhibit the stages of anaesthesia as described by Guedel. This includes the difficult second stage of excitement.

By contrast, IV induction bypasses this second stage.