Anesthesia or anaesthesia is a state of controlled, temporary loss of sensation or awareness that is induced for medical purposes. It may include some or all of analgesia, paralysis, amnesia, and unconsciousness. It may include some or all of analgesia, paralysis, amnesia, and unconsciousness. Today, the most common modern general anesthetics are mixtures of inhalable gases, which include nitrous oxide and various derivatives of ether, such as Isoflurane, Sevoflurane, and desflurane.