This paper aims to take over the rampant phenomenon of the illicit use/abuse for volutary purposes of fentanyl. This synthetic drug is normally used as a potent anaesthetic and analgesic molecule. Unfortunately, in recent decades, this substance has conquered and seduced millions of people in the 'westernised' world, claiming numerous victims, especially young people. To this end, the most recent scientific literature will be examined and the pharmacological effects of both therapeutic and intentional abuse will be considered. Finally, the consequences and psychosocial damage produced will be described.