Despite the large amount of experimental and clinical research that has been carried out in order to find a way to prevent and treat cerebral vasospasm secondary to subarachnoid hemorrhage caused by a ruptured brain aneurysm, this is a devastating complication. The first part of this review outlines the most important and recent experimental studies that have contributed to the advancement in understanding the mechanisms leading to cerebral vasospasm. The second part deals with therapeutic trials, based on this pathophysiological knowledge. The prevention and treatment of vasospasm or "narrowing" of the great arteries of the base of the brain, and the prevention and treatment of the consequence of this arterial "narrowing", the delayed ischemic deficit, reviewing the most accepted medical treatments.

Key words: Subarachnoid haemorrhage; Cerebral vasospasm; Impaired ischemic deficit.