Few other categories of things appear so bound up with questions of agency, power and responsibility as that of ‘drugs’. With over a century of global treaties and prohibition of such substances, we are accustomed to thinking of them as potent things that can hold us in their thrall. Social science approaches, in contrast, tend to downplay the agency and power of the drug itself, showing how such agency and power is distributed among wider contexts. This paper explores themes of drug power and agency through a case study of khat. While relatively weak in terms of pharmacology, khat brims with potency in how people talk about it and its effects. I argue that such talk is crucial for understanding the potency of the substance itself. This talk helps us understand how drug potency is not just a pharmacological property, but an historical, sociological and anthropological one too; such talk also acts to reinforce this potency through influencing expectations of what being ‘under the influence’ entails. Furthermore, while drug potency during moments of intoxication is fleeting, the stories of succumbing to a drug that arise from these moments have a longer-term potency as they are recounted over the years.