An unconscious patient cannot communicate, is unarousable and does not obey commands. Unconsciousness is provoked by a bilateral hemispheric dysfunction or a disturbance of the reticular activating system at the brain stem. There are several causes of unconsciousness, many of which are life threatening (table ). The diagnosis and treatment should therefore progress simultaneously. Immediate intervention will give extra time to discover the cause of unconsciousness and for the initiation of appropriate treatment.