(1) A natural, semisynthetic, or synthetic nitrogen-containing heterocyclic drug that characteristically effects sleep (coma) and relief of pain but also may result in addiction, i.e., a biochemical situation in which the body tissues become so adapted to the drug that they can no longer function normally without it. Natural narcotics are the plant products morphine and codeine (constituents of opium), both of which are alkaloids. Opium is obtained from the seed of the oriental poppy, Papaver somniferens. Semisynthetic narcotics are modifications of the morphine molecule, e.g., diacetylmorphine (heroin), ethylmorphine (“Dionin”), and methyldihydromorphine (metopon). Synthetic narcotics are meperidine, ethadone, and phenazocine (there are other addictive agents that are not narcotics). The sale of narcotics is strictly controlled by law in the U.S. (2) Inducing sleep or coma. Many chemicals that are not narcotics in sense (1) have this property (chloroform, barbiturates, benzene, etc.).