The start of general anesthesia where a patient goes from consciousness to unconsciousness. In adults, induction is often accomplished by administering intravenous medications, like thiopental or propofol. These medications soon wear off, so they are followed by anesthetic gases or an infusion of propofol. Children can often be induced by having them breath in the potent inhaled anesthetics until they fall asleep (thus avoiding an IV until after they are asleep).

An anaesthetic machine - sometimes referred to as a "Boyle's" Machine