The aim of this study was to investigate the therapeutic effectiveness of lacidipine in stroke-prone spontaneously hypertensive rat (SHRSP) with cerebrovascular lesions in comparison with nicardipine. SHRSP were fed 1% saline as drinking water. After the onset of stroke, saline was replaced with water and each drug was administered orally once a day for 3 weeks. In the drug-untreated group, recurrence of stroke was repeated, deterioration and amelioration of neurological deficits (ND) were repeated, and histological examination and measurement of regional blood flow (rBF) using nonradioactive colored microspheres performed at the end of treatment revealed severe damages and significantly decreased rBF in brain and kidney, respectively. In kidney, not only lacidipine (1 mg/kg) but also nicardipine (30 mg/kg) decreased vascular lesions and ameliorated low-rBF significantly. Both drugs also inhibited the recurrence of stroke completely even at a low dose that did not ameliorate severe hypertension. Neuronal damages and ND in each lacidipine-treated group were ameliorated significantly, whereas those in each nicardipine-treated group were slightly improved. Lacidipine at 1 mg/kg alone ameliorated the cerebral low-rBF significantly even at 24 hr after administration. These results suggest that a long-lasting improvement of low-rBF after stroke may be useful in the treatment of SHRSP with cerebrovascular lesions.