The efficacy of nimodipine in decreasing mortality and morbidity of subarachnoid haemorrhage (HSA) is evaluated in 51 patients admitted to the Neurological and Neurosurgery Departments of the Santa Maria Hospital. Reductions of 2 x (0.65, 6.39) of the incidence of ischemia in the total group and of 2.1 x (0.58, 7.79) of mortality in the sub-group with initial severity of less than 4 points of the Hunt score were observed relatively to a comparable group of patients previously admitted who did not receive nimodipine. Randomized clinical trials that tested the effect of nimodipine in the context of HSA are reviewed.