Systemic hypertension and tachycardia are often observed in the acute phase of traumatic brain injury. What causes systemic hypertension after head injury? Is systemic hypertension somehow beneficial to the injured brain? Are vasodilating drugs the first choice for treatment of systemic hypertension after traumatic brain injury? The occurrence of a hyperadrenergic state, the effects of systemic hypertension on the injured brain, the ideal blood pressure, and the management of systemic hypertension after traumatic brain injury are reviewed herein.