In 1984, in connection with the introduction of the calcium antagonist nimodipine, a new strategy for the treatment of subarachnoid haemorrhage (SAH) due to ruptured aneurysm was developed in our hospital. With no rigid regard to "timing" all patients undergo surgery as soon as possible. The only exception being those in Hunt and Hess grades IV and V without space-occupying intracranial haemorrhage and those bearing aneurysms of the vertebrobasilar circulation that are difficult of access. As soon as the risk of rebleeding has been eliminated surgically an active therapy against the possible consequences of SAH--cerebral vasospasm and simultaneous disturbances of autoregulation--is started. It consists in lowering the increased intracranial pressure, raising of mean arterial pressure and improving of rheological properties of the blood in order to prevent delayed build-up of neurological deficit due to ischaemia. It goes without saying that calcium antagonists are given from the very beginning of the patient's treatment even before operation. The advantages of this therapeutic concept are demonstrated by two series of non-selected consecutive patient material. The first series (A; n = 135) was treated between 1981 and 1984 before the change in treatment strategy, the second (B; n = 183) from 1984 to 1986 after that change. The overall mortality in series A was 27%, that in series B 20%. Operative mortality could be reduced from 22% to 16% in patients having undergone early operation and from 6% to 2% in patients with late surgery.(ABSTRACT TRUNCATED AT 250 WORDS)