The article consists of two complementary parts. In the first part, the author sets out a brief description of the events, which he considers have played an important role in the process of the 'drug discourse' construction in the Slovak Republic. Remains of the ideological taboo that has accompanied the use of illegal drugs during the communist era; absence of organizations that would reflect the consequences of illegal drug use upon the basis of modern and valid scientific knowledge; media-fabricated 'moral panic' and 'sensation willing' misinterpretation of reality; and, last but not least, intentional dramatization of the topic by politicians with the aim of gaining electorate. These have been the factors, which, among others, have contributed to the fact, that most of the knowledge constituting the character of the Slovak drug discourse could be characterized as belonging to the 'common sense' type. This in turn had a consequence in establishing a public policy based upon non-valid problem situation identification. The effects (although unintended) of this public policy were mainly revealed by further criminalisation and marginalisation of users of the illegal drugs, whereas almost no support was available for populations of users that had already been excluded and placed at the edge of society. The second part deals particularly with the two so-called 'pillars' of the Slovak drug policy: the prevention of drug demand and the prevention of drug supply. Knowledge backgrounds of methods of the two types of prevention are confronted with the actual and scientifically verified research outcomes in the discussed fields. This critical analysis reveals that most of the knowledge background giving shape to these methods and their implementation presents non-verified, sometimes even non-realistic expectations and images about the nature, causes and consequences of problem drug use. This gives support to the argument set in the first part of the text that methods of ameliorating problem consequences of illegal drug use constructed within Slovak drug discourse are mainly based upon 'common sense' type of knowledge.