The evidence suggests that intravenous magnesium sulfate is clinically safe and beneficial to patients suffering from severe acute asthma. The review addresses a focused clinical question and the criteria used to select articles for inclusion are appropriate. The search strategy was documented and complete, and the methodological quality of the primary trials was addressed. The results indicate that Magnesium Sulfate should be used only in the treatment of severe acute asthma in the emergency department and should not be employed in the routine management of acute asthma.