Violence in emergency departments (EDs) has reached a level that requires concerted action and a shift in attitude - to eradicate a socially and professionally unacceptable peril. In some EDs, violence is a daily occurrence, with nursing staff reporting several episodes each week. Increased societal violence results in an increase in presentations for injury. Anger and pain and the influence of alcohol and drugs contribute to violence spilling over into the ED. The well known "system blockers" to reporting adverse events in hospitals result in under-reporting of violence episodes. Violence in EDs is different from other forms of violence - the aggressor has no overt dominance or power status and, in a setting of care, victims are likely to excuse the behaviour. Strategies to curb violence in EDs include modifying building design, providing security systems and personnel, and training staff in aggression management. The key to successful intervention is a strong preventive orientation that looks for high-risk indicators, and may extend to active physical and behavioural screening.