As the number of new 'psychoactive substances' detected globally has risen exponentially, the policy response of assessing and prohibiting each new substance individually has become increasingly unworkable. In an attempt to disrupt the availability of new as-yet-unscheduled substances, Ireland (2010), Poland (2011), Romania (2012), New Zealand (2013), Australia (2015) and the United Kingdom (2016) have enacted generic or blanket ban legislation that prohibits all 'psychoactive substances' that are not already regulated or belong to exempt categories. How such generic legislation defines 'psychoactive substance' is therefore crucial. While there is a growing critical literature relating to blanket bans of 'psychoactive substances', the Australian legislation is yet to be described or critically analysed. In this commentary, we aim to draw the attention of local and international drug policy scholars to Australia's newest legislative approach to 'psychoactive substances'. Using the Australian experience as a case study, we first describe and trace the origins of this generic banning approach, especially focusing on how 'psychoactive effect' came to be defined. Then, we critically examine the assumptions underpinning this definition and the possibilities silenced by it, drawing on the work of poststructuralist and critical scholars. In doing so, we explore and raise a series of questions about how this legislation works to stabilise drugs, drug harms and drug effects, as well as addiction realities; how the category of 'psychoactive substances' is produced through this legislation; and some of the material-discursive effects which accompany this rendering of the 'problem'. We offer this commentary not as a comprehensive discussion of each of these elements but rather as a starting-point to promote further discussion and debate within the drug policy field. To this end, we conclude with a suggested research agenda that may help guide such future work.