Since the 1920s certain psychoactive substances have been controlled by specially created international agencies. More recently, governments have committed themselves to using evidence in policy-making. Yet, as the ban on khat in the UK and other countries shows, the assessment process is a perfunctory rather than a decisive component. The Home Secretary set aside scientific advice and bases the decision to ban on considerations outside the health risk ratio, including crime control and counter-terrorism. However, experience shows that prohibiting substances when demand remains strong is inherently criminogenic. Indeed, the khat ban would appear to play into the hands of radical Islamist organizations. In this article, Axel Klein discusses how political calculations overrule evidence and how this is facilitated by international drug control agencies. Using the term ‘social system’ to explain the relentless extension of bureaucratic remit, he argues that control would now appear inevitable for any substance defined as a drug, regardless of evidence and consequence. As this has implications for other culture-bound peculiar substances or ‘genussmittel’ he suggests ditching the term ‘drug’ altogether.