Codeine tablets act as analgesic, sedative and antitussive. 1. Analgesia: It can selectively agonize opioid receptors in the glial region of the spinal cord, medial thalamus, ventricles and gray matter around the conduit to produce analgesia. 2. Sedation: It can activate the limbic system, the nucleus accumbens and the ventral dorsal capping area of the midbrain-limbic lobe, producing sedative and euphoric effects. It can also relieve pain-induced anxiety, tension, fear and other emotional reactions, and improve pain tolerance. 3. Cough suppressant: can directly inhibit the medulla oblongata cough center, so that the cough reflex to reduce or disappear, produce cough suppressant effect. Codeine is a toxic narcotic restricted psychotropic drug, addictive for long-term use, constipation, urinary retention, upright hypotension, respiratory depression and other side effects may occur during use, it is recommended that the medication be used reasonably under the guidance of a doctor.