Background: Cerebral edema and raised intracranial pressure are common problems in neurological intensive care. Osmotherapy, typically using mannitol or hypertonic saline (HTS), has become one of the first-line interventions. However, the literature on the use of these agents is heterogeneous and lacking in class I studies. The authors hypothesized that clinical practice would reflect this heterogeneity with respect to choice of agent, dosing strategy, and methods for monitoring therapy. Methods: An on-line survey was administered by e-mail to members of the eurocritical Care Society. Multiplechoice questions regarding use of mannitol and HTS were employed to gain insight into clinician practices. Results: A total of 295 responses were received, 79.7% of which were from physicians. The majority (89.9%) reported using osmotherapy as needed for intracranial hypertension, though a minority reported initiating treatment prophylactically. Practitioners were fairly evenly split between those who preferred HTS (54.9%) and those who preferred mannitol (45.1%), with some respondents reserving HTS for patients with refractory intracranial hypertension. Respondents who preferred HTS were more likely to endorse prophylactic administration. Preferred dosing regimens for both agents varied considerably, as did monitoring parameters. Conclusions: Treatment of cerebral edema using osmotically active substances varies considerably between practitioners. This variation could hamper efforts to design and implement multicenter trials in neurocritical care. © 2010 Springer Science+Business Media, LLC.