Several endothelium-derived contracting factors (EDCFs) are produced that have functional effects in the cerebral circulation. Although most studies suggest that EDCFs do not affect resting tone of cerebral blood vessels under normal conditions, recent findings indicate that EDCFs contribute importantly to vascular dysfunction in disease states. This review will focus on the nature and influence of EDCFs produced under pathophysiological conditions and that may potentially contribute to cerebral ischemia, vasospasm, or stroke...