Aggression is defined as any verbal, non-verbal or physical behaviour that threatens or harms others or property. (1) Aggression can be a symptom of a psychiatric illness or a medical illness. (2,3) Psychiatric symptoms can be caused by a medical illness, (4-8) occur coincidentally with a medical illness (7,9) or be a consequence of a medical illness. (10,11) All aggressive patients are therefore subject to mandatory screening for a medical illness by emergency department (ED) doctors in the EDs of Addington and King Edward VIII hospitals in Durban. ED doctors argue that screening is unnecessary because: (i) the prevalence of a causal medical illness in this setting is not known (there is a perception that the prevalence is so low that screening is not warranted); and (ii) the current screening protocol delays admission, increases the potential for injury to staff and patients, and adds to the patient load in a busy, resource-constrained ED (a doctor has to attend to more than 30 patients in an 8-hour shift at each of these two hospitals). Similarly, Jonsson et al. (12) reported that in the severely under-resourced ED at Chris Hani Baragwanath Hospital, Johannesburg, aggressive patients are sometimes referred to psychiatric services before a medical illness is excluded. This premature referral makes it difficult for patients to access medical care once they have been labelled as mentally ill.