General anesthetics are agents that bring about reversible loss of sensation and consciousness. There are four stages of general anesthesia. General anesthetics may be intravenous or inhalational. Inhalation anesthetics are either gases or volatile liquids. Given by inhalation, they are absorbed by the pulmonary circulation. On attaining adequate concentration in the brain, they produce general anesthesia. Nitrous oxide produces light anesthesia without significant depression of respiration or vasomotor centre. Ether is a colorless volatile, inflammable liquid and vapors are irritating. Halothane is a non irritant, non inflammable and volatile liquid. It is a commonly used anesthetic with analgesics and muscle relaxants used as along adjuvants. Enflurane and isoflurane are similar to halothane with minor differences. Desflurane and sevoflurane are newer agents which allow very rapid induction and recovery because of low solubility in blood. Intravenous anesthetics allow an extremely rapid induction because the blood concentration can be raised rapidly. Thiopentone sodium is used for induction of anesthesia. Propofol is preferred for ‘day-cases’. Ketamine produces dissociative anesthesia. Prior to anesthesia, certain drugs are administered in order to make anesthesia safer and more pleasant and is known as pre-anesthetic medication.