Cerebral vasospasm (CV) is the leading cause of morbidity and mortality occurring after subarachnoid hemorrhage (SAH). Etiopathogenesis of CV is multifactorial. Selenium is the cofactor of the glutathione peroxidase (GSH-Px) enzyme which is a very important defense mechanism against antioxidants. According to the literature, oxidants are known to play a remarkable role in the pathogenesis of vasospasm occurring after SAH. Therefore, many studies have been conducted with antioxidant agents, based on the theory that elevated activity of GSH-Px enzyme might prevent the development of CV after SAH. Majority of those studies reported positive results. However, as a result of our literature review, we came across no study which involves the investigation of the role of selenium alone in the prevention of CV after SAH. In our study, we aim to find the answer to the following question: "Can selenium alone prevent cerebral vasospasm following SAH at early stage?"