Cerebral arterial vasospasm is the major complication of subarachnoid haemorrhage. This process of unclear aetiology causes significant increases in the morbidity and mortality of patients with subarachnoid haemorrhage. In this study all physiopathological characteristics of subarachnoid haemorrhage were established in a 3-way model in cats. Using this model, we investigated the efficacy of defibrotide in preventing cerebral arterial vasospasm following subarachnoid haemorrhage. A1though the process of vasospasm could not be prevented by the use of defibrotide, our results suggest that defibrotide can significantly decrease delayed histopathological damage after subarachnoid haemorrage.