While reversing established central nervous system damage is clearly a difficult task, preventing or limiting ongoing destructive processes in the brain may be a more achievable goal. The monitoring technology required to detect clinically significant adverse secondary events has evolved considerably in the past few years. As a result it has become evident that such adverse events are common in the head injured patient and that they can have a dramatic effect on outcome. Furthermore, it is also becoming clear that these secondary insults are, to a significant degree, preventable. It is likely that simple physiological maneuvers, such as maintaining the cerebral perfusion pressure, as well as newer pharmacological agents, will be useful for this purpose. The pathophysiology of brain swelling remains unclear and deserves continued study. This review describes the factors responsible for secondary brain injury, some practical ways of identifying and managing them, and certain newer pharmacological agents that may be valuable in the clinical setting.