Heroin (diacetylmorphine or morphine diacetate, also known as diamorphine (BAN, INN)) and commonly known by its street names of H, smack, boy, horse, brown, black, tar, and others is an opioid analgesic originally synthesized by C. R. Alder Wright in 1874 by adding two acetyl groups to the molecule morphine, which is found naturally in the opium poppy. It is the 3,6-diacetyl ester of morphine.