General anesthesia is a controlled, reversible state characterized by amnesia, analgesia, akinesia, and reflex blockade achieved through a combination of drugs. It is indicated for patients who cannot cooperate for procedures, extreme anxiety, or significant medical conditions, but presents risks such as impaired protective reflexes and the need for specialized assistance. Various theories explain its mechanism, with the membrane expansion theory being widely accepted, alongside considerations for preoperative evaluation, patient preparation, and the use of specific anesthetic agents.