Traumatic injuries to the brain or spinal cord cause irreversible tissue damage by at least three mechanisms: through consequences of mechanical disruption of neurons or their projections; through biochemical or metabolic changes that are initiated by the trauma; and through reactive inflammatory or gliotic changes. During the past decade, considerable data have been accumulated regarding cellular and biochemical events associated with posttraumatic tissue damage. This has led to the application of pharmacological strategies to limit secondary injury and subsequent neurological deficits. Such research has resulted in the first effective treatment of human spinal cord injury, with other promising treatments in late preclinical or early clinical development.