Vidian neurectomy was performed in 28 patients with perennial nasal allergy and changes in symptoms and complications 3-7 years after the operation were examined in order to evaluate the effect and limitation of the operative therapy on nasal allergy. Vidian neurectomy could completely stop hyperrhinorrhea in all cases for a limited period of time. In 43% cases, however, recurrence of rhinorrhea was observed. As for nasal obstruction, disappearance of the symptom or marked improvement was noted in only 33% of the cases and in many cases, intranasal operation was also required for improvement of nasal obstruction. Disappearance of nasal obstruction and marked improvement when intranasal operation was also applied was noted in 85% of cases. If the grade one improvement was included, general improvement of the symptoms of nasal allergy lasted in 86-90% of the cases. Effect of operative removal of sneezing, nasal obstruction, and rhinorrhea which are considered to be defensive reflex, on lower airway or whole body was examined by pulmonary function tests and measurement of serum total IgE level. There were no postoperative tendency to development of obstructive ventilatory impairment at the lower airway or to increase in serum total IgE level. There is room to improve the operative technique to inhibit reinnervation, however, the merit of Vidian neurectomy is large for selected patients with perennial nasal allergy, because when combined with intranasal operation to relieve nasal obstruction it can remove the symptoms in high percentage of cases by a single performance. © 1979 Springer-Verlag.