MEDICAL MANAGEMENT OF cerebral edema and elevated intracranial pressure (ICP) is a critical component of perioperative care in neurosurgical practice. Traumatic brain injury, arterial infarction, venous hypertension/infarction, intracerebral hemorrhage, subarachnoid hemorrhage, tumor progression, and postoperative edema can all generate clinical situations in which ICP management is a critical determinant of patient outcomes. Although osmotic agents are among the most fundamental tools to control ICP, prospective data to establish clear guidelines on their use are lacking. Hypertonic saline is emerging as an alternative to mannitol. Early data suggest that indications for each agent may ultimately depend on ICP etiology.