BACKGROUND:S100B protein in patients with cardiac arrest, hemorrhagic shock and other causes of global cerebral ischemic injury will be dramatically increased. Ischemic brain injury may elevate the level of serum S100B protein and the severity of brain damage.METHODS:This article is a critical and descriptive review on S100B protein in serum after ischemic brain injury. We searched Pubmed database with key words or terms such as “S100B protein”, “cardiac arrest”, “hemorrhagic shock” and “ischemia reperfusion injury” appeared in the last five years.RESULTS:S100B protein in patients with cardiac arrest, hemorrhagic shock and other causes of ischemic brain injury will be dramatically increased. Ischemic brain injury elevated the level of serum S100B protein, and the severity of brain damage.CONCLUSION:The level of S100B protein in serum is elevated after ischemic brain injury, but its mechanism is unclear.