목적: Rhinitis is a common inflammatory response of nasal mucosa with clinical symptoms of rhinorrhea, nasal obstruction, sneezing, and itching of nose and eyes. Especially, allergic rhinitis affects 25% of the world’s population and its prevalence continues to increase annually. Recently, measuring nasal nitric oxide (nNO) becomes a useful noninvasive secondary method for evaluating severity of upper airway inflammation. The aim of this study is to evaluate whether nNO reflects the treatment effect. 방법:Levels of nNO were measured from the patients who visited otorhinolaryngology department for rhinitis symptoms with a NO analyzer (NIOX VERO) from December 2021 to November 2023. Every patient received treatment with intranasal corticosteroid spray, oral antihistamine and/or oral leukotriene antagonists. Levels of nNO were repeatedly measured after the treatment. Total nasal symptoms score (TNSS) before and after the treatment were evaluated and the difference between the score was measured. Laboratory tests, including serum total immunoglobulin E (IgE), blood eosinophil percent and count, and skin prick test were performed at the initial visit. Total nasal symptom score (TNSS) and quality of life (QOL) questionnaire were evaluated before and after the treatment. 결과:A total of 46 patients were included in this study. According to skin prick test, 39 patients were considered as allergic rhinitis (AR, 84.8%) and 7 patients were considered as non-allergic rhinitis (NAR, 15.2%). TNSS and score of QOL questionnaire after the treatment were significantly decreased compared to those before the treatment (TNSS p<0.001, QOL questionnaire p=0.002). The difference between the nNO and TNSS significantly shows positive correlation (p=0.045). Pre- treatment blood eosinophil percent was significantly higher in patients with larger nNO difference (p=0.022). There was no significant correlation between the nNO difference and pre-treatment serum total IgE, but it tended to be correlated (p = 0.887). According to QOL questionnaire, sleep disturbance, generalized symptoms, practical problems, nasal symptoms, and ocular symptoms categories showed significant correlation to nNO difference (p<0.05). Activity limitation and emotional problems categories did not significantly be related to nNO difference, but still tended to be correlated. Lastly, pre-treatment TNSS were higher when initial nNO levels were higher, even it is not significantly correlated. 결론:In this study, the changes in TNSS and QOL score correlated to the change in nNO level in rhinitis patients after treatment. As nNO levels were considerably decreased after the treatment, nNO may be used as objective tool for evaluating treatment effect of rhinitis.