Rationale and aim: Nasal congestion is a common symptom in allergic and non-allergic rhinitis, rhinosinusitis and nasal polyposis. Although various pharmacotherapy options exist, no agent is universally efficacious. The aim of this study was to evaluate the clinical effectiveness efficacy of Narivent, which is an osmotically acting medical device with anti-oedematous and anti-inflammatory effects, in a long-term (30 days) treatment. Methods: A single-centre prospective study with a pre-post design was conducted with consecutive enrolment in an Italian Otolaryngology Department of 56 both genders patients with persistent nasal congestion. Patients received 2 puffs of Narivent into each nostril 2 times a day over the course of 4 weeks. The severity of symptoms was assessed subjectively as measured by a 0 to 10 visual analogue scale (VAS) and the presence/absence of symptoms and signs. Differences in subjective and objective severity measures before and after treatment were compared using Paired-Sample Wilcoxon Signed Rank Test. Results: A significant improvement after treatment (p