Despite the publication of several randomized controlled studies, there is still 
much debate on whether magnesium sulfate improves outcome in patients with 
aneurysmal subarachnoid hemorrhage. Here we present data to assess the clinical 
effectiveness of magnesium sulfate in the prevention of cerebral vasospasm in 
patients who have suffered from aneurysmal subarachnoid hemorrhage. The EMBASE 
and PubMed databases were searched using the following terms: "magnesium 
sulfate" or "MgSO(4)" with "subarachnoid hemorrhage" or "cerebral vasospasm". A 
manual search of the bibliographies of relevant articles was also conducted. Two 
co-authors of the present study designed the meta analysis of published 
randomized clinical trials and extracted the data. Data were analysed by using 
Review Manager 4.2 from the Cochrane Collaboration (Oxford, UK). Five published 
manuscripts were identified according to the screening criteria. The occurrence 
of poor outcome (death, vegetative state, or dependency) in patients treated 
with magnesium sulfate was less likely than control group patients (odds ratio 
[OR] 0.54 [95% confidence interval, CI 0.36-0.81]). Mortality rates did not 
differ between magnesium sulfate (14%) and control treated (12%) patients (OR 
1.16 [95% CI 0.51-2.65]). Our results indicate that although there was reduced 
likelihood of a poor outcome for patients treated with magnesium sulfate after 
SAH, patient mortality was not improved.