A nebulizer uses air or preferably oxygen to aerate and transport an anesthetic for providing topical anesthesia to the airway passages of a patient undergoing analysis or treatment by any of several medical instruments used to traverse the airway passages. The nebulizer is preferably applied in connection with fiberoptical diagnostic and therapeutic instruments, such as bronchoscopes, endoscopes and laryngoscopes, and many variations of these instruments. Other liquid, aerosol, and gaseous drugs may also be administered with the nebulizer.