The principle of anesthetics is to act on the nervous system of the body, by blocking the nerve conduction pathway, thus making the body unable to perceive pain. They are widely used in all kinds of surgeries. Anesthetics can be divided into general anesthetics and local anesthetics. General anesthetics act on the brain and the center of the human body, causing central inhibition, so that the brain and the center of the loss of consciousness, unable to perceive pain. Local anesthetics, through its application in the local area, mainly acts on the nerve conduction, so that the local nerves are blocked, blocking the nerve conduction pathway, so that the pain can not be upward conduction to the center, so as to achieve the effect of anesthesia. Narcotics belong to the national strictly controlled drugs, without a doctor’s prescription should not be used without authorization, so as not to cause serious consequences.