Although in recent years a tendency towards early operative clipping of the aneurysm to prevent rebleeding has emerged, rebleeding is still the major cause of poor outcome, more often than cerebral ischaemia.

Rebleeding is thought to originate from fibrinolysis of the clot at the site of the ruptured aneurysm. Because antifibrinolytic agents inhibit fibrinolytic activity and rapidly cross the blood-brain barrier after subarachnoid haemorrhage, antifibrinolytic therapy may reduce the rate of rebleeds and result in a decrease of morbidity and mortality.

Since the first report, published in 1967, on antifibrinolytic treatment in patients with subarachnoid haemorrhage, over 30 studies on antifibrinolytic therapy in aneurysmal subarachnoid haemorrhage have been published. Unfortunately most are uncontrolled and only a minority of the controlled studies is randomised. The randomised studies are the subject of this systematic review that investigates the effect of antifibrinolytic treatment on clinical outcome in patients with aneurysmal subarachnoid haemorrhage. In addition we analysed the reported rates of rebleeding, cerebral ischaemia, and hydrocephalus.