Relapse to drug abuse or addiction is thought to result, in many cases, from exposure to cues that elicit drug-related memories. The term memories is used here not in its everyday sense, but in a sense that corresponds more closely to emotional associations for example, the association between the sight of a crack pipe and a set of responses such as rapid heartbeat and desire for cocaine. Studies in rodents and humans show that this type of memory is reconsolidated (actively re-stored) each time it is reactivated, and that the reconsolidation process can be disrupted by propranolol. Such disruption does not erase the autobiographical memory of an event, but instead weakens the link between that memory and an emotional response. Human studies are needed to determine whether propranolol disrupts reconsolidation of drug-cued memories in addicted individuals; this would present a novel and exciting therapeutic possibility for preventing craving and relapse.