This study prospectively examined the intranasal distribution of nasal spray after nasal septal correction and decongestant administration.A cohort of 20 patients was assessed for the distribution of nasal spray before and after nasal septum surgery.Sprays were dyed and administered one puff per nostril when patients hold their head up in an upright position.Before and after decongestant administration,the intranasal distribution was semi-quantitatively determined by nasal endoscopy.The results showed that the dyed drug was preferentially sprayed onto the nasal vestibule,the head of the inferior turbinate,the anterior part of septum and nasal floor.As far as the anterior-inferior segment of the nasal cavity was concerned,the distribution was found to be influenced neither by the decongestant nor by the surgery (P＞0.05).However,both the decongestant and surgery expanded the distribution to the anatomical structures in the superior and posterior nasal cavity such as olfactory fissure,middle turbinate head and middle nasal meatus.No distribution was observed in the sphenoethmoidal recess,posterior septum,tail of inferior turbinate and nasopharynx.It was concluded that nasal septum surgery and decongestant administration significantly improves nasal spray distribution in the nasal cavity.