Subarachnoid haemorrhage is a severe illness with a high mortality and morbidity. Its diagnosis is considered in the case of a brutal, violent and unusual headache. It is confirmed rapidly with the conventional techniques such as CT-scan and lumbar puncture. The main complications (ischaemia, rebleeding, hydrocephalus) occur during the first two weeks and are a usual event in case of a lack of diagnosis or specialised medical, surgical and radiological management. Among the complications, rebleeding badly affects prognosis, and only early surgery or interventional radiology may improve the outcome. Delayed ischaemia may be prevented by medical management with correction of hypovolaemia and administration of calcium antagonists, before and after surgery, particularly between the 4th and the 10th day. When signs of ischaemia occur, aggressive treatment should be administered in order to improve cerebral perfusion pressure and cerebral blood flow. The treatment is aimed to prevent the complications of subarachnoid haemorrhage and to establish optimal conditions for surgical and radiological procedures.