Acute behavioural disturbance (ABD) is a clinical emergency which typically affects overweight men in their mid-thirties who chronically misuse illicit stimulants. People with ABD are most likely to be seen in police custody or emergency departments, therefore nurses working in these areas must be able to recognise the signs and symptoms and know how to respond appropriately. Presentation varies, but the signs and symptoms commonly include extreme agitation, hyperthermia, hostility and exceptional strength without fatigue. Further, it is important to recognise that people with ABD are at risk of developing metabolic acidosis, hyperkalaemia, rhabdomyolysis or disseminated intravascular coagulation. This article gives an overview of ABD and describes the main elements of management and treatment.