The safety and efficacy of epoetin beta for treating acute stroke (within 8 hours) in humans have been confirmed in a double blind, randomized, placebo-controlled clinical trial, which uses high dose intravenous epoetin beta (3,3000 IU/50 ml/30min/day, three days, with a cumulative dose 100,000IU) [Ehrenreich 2002]. No associated changes in blood pressure, haematocrit, haemoglobin, and red blood cell count are found in this trial [Ehrenreich 2002]. Only the reticulocyte count increases 29.2 ±10.0% on the 4th day after the last dose of EPO [Ehrenreich 2002]. This systemic administration of EPO also has led to a 60- to 100-fold increase in CSF levels and does not require a breakdown of the blood-brain barrier (BBB) [Ehrenreich 2002]. Patients who are treated with EPO have a lower and earlier surge of serum S100 (secreted by reactive astrocytes and functional disturbances of membrane integrity of brain cell membrane) and thereafter return to within the normal limits sooner than the placebo [Ehrenreich 2002]. This earlier return of serum S100 towards the normal level implies that the inflammatory processes and/or BBB integrity can be improved more rapidly by systemic EPO therapy [Ehrenreich 2002]. The beneficial effects on stroke patients continue throughout 30 days, particularly for those with moderate to severe strokes [Ehrenreich 2002].