We investigated in a consecutive series of 134 patients with aneurysmal subarachnoid hemorrhage whether institution of antihypertensive treatment was related to the incidence of cerebral ischemia and rebleeding. The aim of hypertensive treatment was to reduce the diastolic blood pressure to levels below 100 mm Hg. There was no difference in outcome between patients with or without antihypertensive drugs. Rebleeding was less frequent in patients with antihypertensive treatment (12/80 patients (15%) versus 18/54 patients (33%) without anti-hypertensive treatment (p = 0.012)). Nevertheless, patients with anti-hypertensive treatment had, on average, still higher blood pressures than untreated patients. Conversely, infarction occurred more often in patients with anti-hypertensive treatment (34/80 patients (43%) versus 12/54 (22%) without antihypertensives (p = 0.03)). This relationship was partly explained by co-existing hyponatremia. Our results suggest that the need for antihypertensive treatment is questionable, since the prevention of rebleeding is offset by an increased risk of cerebral infarction.