The authors evaluated the systemic and ocular hypotensive effects of nicardipine hydrochloride (Perdipine:NH) in 31 cases with acute hypertension (over 160/95 mmHg) during cataract surgery. All cases received an intravenous bolus injection of NH 30 micrograms/kg. Blood pressure and intraocular pressure were compared with level at rest, a preoperatively and 5 minutes after the administration of NH. Blood pressure significantly elevated from 136.9 +/- 10.6/73.4 +/- 10.2 mmHg at rest to 187 +/- 11.5/98 +/- 13.1 mmHg preoperatively (p less than 0.001), but it significantly reduced to 125.6 +/- 13.1/67.1 +/- 8.3 mmHg 5 minutes after the administration of NH (p less than 0.001). On the other hand, in the same way an blood pressure changed, intraocular pressure significantly elevated from 13.3 +/- 2.8 mmHg at rest to 19.8 +/- 2.9 mmHg preoperatively (p less than 0.001), but significantly reduced 17.1 +/- 3.0 mmHg 5 minutes after administration of NH (p less than 0.001). The hypotensive effect of NH continued for over 90 minutes. There were no side effects apart from mild tachycardia in all cases. NH is safe, easy to administer and useful for control of acute hypertension during limited-period surgery such as cataract surgery.