Mannitol is widely used in the control of raised ICP following TBI. Its use is advocated in two circumstances. First, a single administration can have short term beneficial effects, during which further diagnostic procedures (eg, CT scan) and interventions (eg, evacuation of intracranial mass lesions) can be accomplished. Second, mannitol has been used as a prolonged therapy for raised ICP. There is, however, a lack of evidence to recommend repeated, regular administration of mannitol over several days. Although there are data regarding its basic mechanism of action, there are few human studies that validate different regimens of mannitol administration.