<![CDATA[The rapid emergence of New Psychoactive Substances (NPS) has created regulatory gaps because modifications to their chemical structures enable new substances to circulate before they are formally classified as prohibited drugs. This study examines how sadd al-dhariah can be operationalized as a preventive framework for addressing regulatory gaps in NPS control in Indonesia without undermining the principle of legality. It employs doctrinal legal research using statutory, conceptual, and comparative approaches. Primary and secondary legal materials concerning NPS regulation in Indonesia, Malaysia, and Turkey were examined through legal interpretation and comparative analysis. The analysis shows that Indonesia's substance-by-substance scheduling mechanism has not adequately responded to the rapid development of NPS, thereby limiting law enforcement against substances not yet included in official schedules. Malaysia similarly relies primarily on periodic scheduling, whereas Turkey combines individual scheduling with generic definitions based on chemical structures. These comparative findings provide relevant lessons for developing a more adaptive regulatory mechanism in Indonesia. From the perspective of sadd al-dhariah, controlling precursor materials, production, digital promotion, and distribution constitutes a legitimate preventive measure to protect human intellect and life. However, preventive regulation must be supported by scientific precision, procedural accountability, proportionality, and safeguards against overcriminalization. This study concludes that sadd al-dhariah can support adaptive NPS control when implemented through measurable chemical definitions, forensic verification, an early warning system, transparent classification procedures, and judicial oversight. It contributes a preventive legal framework that integrates Islamic legal reasoning with legal certainty and regulatory responsiveness.]]>
