We describe the case of a 55-year-old female patient who presented for clipping of cerebral artery aneurysm that had ruptured 8 h before. Anesthesia induction was uneventful. After adequate positioning of the patient, two injections of a saline solution containing ornipressin (POR 8) were given into the scalp. Before surgical incision the patient developed a hypertensive reaction with arterial blood pressure of 230/140 mm Hg and heart rate 140/min. Pharmacologic intervention decreased the blood pressure and heart rate to normal values within 4 min. Upon surgical opening of the skull, the dura was found to be extremely noncompliant, and the pupils became wide and nonresponsive to light. Acute rebleeding was diagnosed, and the patient was sent back to the intensive care unit without clipping of the aneurysm and was declared brain-dead 12 h later. A Cushing response following acute rebleeding and other factors that might have caused the hypertensive crisis are discussed in detail. Anesthetic agents and adjuncts are assessed in terms of their influence on intracranial pressure and their protective action on the brain. Special consideration is given to subcutaneous ornipressin injection, which is known to be associated with cardiovascular side effects. Deep neuroleptanesthesia is recommended as the anesthetic technique of choice for clipping of cerebral artery aneurysms. Antihypertensive agents without cerebrovascular side effects should be used to treat hypertensive reactions.