The common causes of dangerously increased intracranial pressure are cerebrovascular disease and head injury. Glycerol has been mostly used in neurological patients who have increased intracranial pressure. The mechanism depends on the different osmolalities between blood vessel and brain parenchyma leading to fluid shift from brain parenchyma into blood vessel, resulting in decreasing intracranial pressure. Most studies found that glycrol can decrease intracranial pressure but it has no effect on mortality or morbidity. The clinical utility of glycerol in neurological disease is reviewed in this article.