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heroin
(HAYR-oh-win) - A highly addictive substance once used to treat severe pain but is now illegal to use or sell in the United States. It is made from morphine, a natural substance found in the seed pods of the opium poppy plant. Heroin works by binding to mu opioid receptors in the central nervous system, which blocks pain signals and changes how the body responds to pain. It is a type of analgesic (pain reliever) and a type of opiate. Also called diacetylmorphine and diamorphine.
