The aim of present study is to observe changes of ciliary activity and histopathologic findings after applying phenylephrine to the cultured human nasal mucosa. The nasal mucosa, obtained from the inferior turbinates in healthy subjects without any nasal symptoms or signs, was cultured ans then, exposed to phenylephrine solution at varying concentrations, containing no preservatives. Ciliary activity was observed under the inverted microscope and the histopathology of the mucosa was examined by light microscopy. 1, 3, 6, 12, 24, and 48 hours after exposure, respectively. Phenylephrine impaired ciliary activity and induced mucosal injury according to the concentration and the exposure time. The higher the concentration of phenylephrine was and the longer the exposure time was, the more the above functional and morphologic changes were. It was likely that the morphologic changes were followed by functional changes. Once ciliary activity disappeared, it was not restored at least for the next 48 hours. Furthermore, histopathologic changes also results from applying phenylephrine at the concentration of clinical use. In conclusion, phenylephrine as a topical vasoconstrictor should be administered for the minimal period even at clinical dose.