In the last two decades our understanding of the pathophysiology of severe head injury has significantly increased. It has become evident that secondary neuronal damage may occur and should be prevented. It is ischemia, similar to that seen with stroke and aneurysmal subarachnoid hemorrhage, that causes secondary brain damage. Therefore, careful monitoring of blood pressure is indicated, and the treatment of arterial hypotension/hypertension should begin as soon as possible. Moreover, there are some new pharmacological concepts for changing the threshold for ischemia in brain tissue. At the present time, however, valid data concerning clinical use are still not available. Therefore, mild hyperventilation and sedation during the initial post-traumatic phase and lowering of intracranial pressure by osmotherapeutics remain the most important treatment modalities, as they were 20 years ago.