Intubation conditions and pressor response were assessed in 30 healthy patients undergoing awake nasotracheal intubation. The patients were premedicated with peroral diazepam. All the patients were sedated with intravenous diazepam 0.1 mg/kg. Alfentanil 20 micrograms/kg or saline was administered in a double-blind fashion. Alfentanil caused moderate respiratory depression but significantly improved conditions for fiberoscopy. In the control group, arterial pressures and heart rate increased significantly immediately after tracheal intubation. These responses were attenuated by alfentanil.