Heroin, also called diacetylmorphine, is highly addictive morphine derivative. Heroin is made by treating morphine with acetic anhydride; causing acetylation of the two hydroxyl groups of morphine. The resulting substance is four to eight times as potent as morphine. (Morphine is an alkaloid found in opium, which is the dried milky exudate obtained from the unripe seed pods of the poppy plant.)