Delayed ischemic deficits (DID) and strokes caused by low cerebral blood flow (CBF) are major sources of poor outcome following aneurysmal subarachnoid hemorrhage (SAH). DID are often accompanied by vasospasm and abnormalities in cerebrovascular autoregulation, an important reflex involved in the defense against low CBF. Assessment of vasospasm and impaired autoregulation can be conveniently measured non-invasively by use of transcranial Doppler (TCD) and the transient hyperaemic response test (THRT). Vasospasm and abnormalities in the THRT can predict those patients who are at risk of developing DID. In this study, the investigators wish to explore the neuroprotective and angiogenic effects of systemic erythropoietin (EPO) therapy on vasospasm and autoregulation following SAH, and examine whether any improvements translate into reduced incidences of DID and poor outcome. Eighty patients with SAH will be recruited over one year to receive three doses in the first week of either intravenous epoetin beta 30000 IU or placebo (0.9% saline) 50 ml/30 min as part of a randomized, double-blind, placebo-controlled trial. The investigators propose daily TCD assessment for detecting vasospasm and abnormal autoregulation. Outcome measures will examine the influence of EPO therapy on the incidence, severity, and duration of vasospasm, abnormal autoregulation, and DID.