Heroin, a derivative of opium, was first created in 1874 and was marketed in 1898 as a cough medicine by a German pharmaceutical company. In Britain, the dispensing of heroin was initially restricted to pharmacists under the general pharmacy and poisons legislation. Just 22 years later, the Dangerous Drugs Act 1920 made it a criminal offence to manufacture, sell, distribute or possess heroin for non-medical purposes. This article attempts to explain this major shift in the regulation of heroin by drawing on David Garland's influential book Punishment and Welfare. Garland traces the fundamental transformation in social regulation that occurred at the turn of the twentieth century, arguing that a new penal-welfarism emerged which was to underpin the welfarist politics that held sway until the 1970s. It is argued that by locating the shift in heroin regulation in this wider context of social change, some new insights are revealed. In conclusion, some implications of this argument for contemporary approaches to heroin are discussed. © 2007 Elsevier Ltd. All rights reserved.