Nasal provocative testing is the introduction of a specific factor into the nose and the subsequent assessment of the pathophysiologic changes induced by the challenge. The provocative test primarily affects the nasal airway but also may affect the adjacent organs, including the eustachian tube, middle ear, sinuses, and lower respiratory tract. Recent advances in the measurement of nasal airway resistance with microcomputer-assisted rhinomanometry have improved the objective assessment of nasal airway obstruction. Eustachian tube obstruction has been shown after nasal provocation by a new procedure, sonotubometry, which can be performed in series with rhinomanometry and pulmonary spirometry. As will be described these procedures have helped elucidate the extent and pathophysiology of diseases affecting the upper airway, especially allergic rhinitis. At present, nasal provocation is primarily a clinical investigative test. It is anticipated that with further development and refinement, it can be used to a greater extent in the diagnosis and management of nasal diseases.