The treatment of subarachnoid haemorrhage caused by aneurysm in comatose patients with or without midbrain symptoms is a matter of controversy. The question is, which comatose patients will profit from aneurysm surgery and which will not? In a retrospective study, 573 patients were examined between 1986 and 1992. Of these, 116 were in poor condition (Hunt and Hess Grade IV or V). The following management protocol was used: after computer tomography, a decision was made whether intensive medical treatment was performed or not. The reason for not operating was essentially the severity of the cerebral haemorrhage and poor or absent intracranial filling on angiography. Extracerebral causes were renal failure, sepsis, liver cirrhosis and pulmonary embolism. The direct early aneurysm operation was performed in the clinical deterioration phase in patients with space-occupying haematomas. In dilatation of the ventricle system, external drainage was initially positioned, in the case of bilateral haematocephalus, two-sided drainage was positioned, then intensive medical treatment and angiography were performed. The aneurysm operation was then ruled out if there was no clinical improvement. Aneurysm operation was performed on 57 of the 116 patients; 13 died, 32 showed a good and 12 a poor or fair outcome. 15 patients had mid-brain syndrome, and 5 of them died. Based on our experience, we draw the following conclusion: the Hunt and Hess scale alone is not a sufficient basis for decision taking. Some of the comatose patients, even in mid-brain syndrome, profit from an early operation.(ABSTRACT TRUNCATED AT 250 WORDS)