Patients who present to an emergency department (ED) with a problem related to illegal drug use can be difficult to identify and are perceived to generate a significant workload for staff. This study suggests that illicit drug use may be more common than previously reported and also that the impact on the ED is perceived by staff to be disproportionately high compared with the actual numbers of patients presenting with complaints related to illicit drug use. We conclude that the over estimation by staff is directly related to the challenges that staff working within the ED setting believe this group of patients pose.