Rhinosinusitis disorders are almost regularly associated to Cystic Fibrosis (CF). The basic defect in CF is a dysfunction of chloride channels in exocrine glands which equally concerns upper airway mucosa. It leads to retention of secretions and consecutive chronic inflammation with bacterial superinfection.

In CF rhinosinusitis can restrict quality of life, give cause to repeated ear, nose, and throat (ENT) surgery and accelerate disease progression by bacterial acquisition into the airways.

The multicenter, randomized, double-blind, placebo-controlled, prospective clinical trial aims at the evaluation of a sino-nasal inhalation of sodium chloride 6% compared to isotonic saline with respect to ENT-related quality of life which is influenced by mucus retention and the resulting inflammation.

Inclusion Criteria:

• Subject has a confirmed diagnosis of cystic fibrosis based on: 2 positive sweat chloride tests and/or genetic characterization
• Subject is 8 years of age or older
• informed consent of the patient or legal representative
• Women of childbearing potential are only included into the study, if they are using an effective method of birth control during the protocol (failure rate <1% e.g. implants, combined oral contraceptives, injectables, some intrauterine devices, sexual abstinence or vasectomised partner)

Exclusion Criteria:

• Subject has no chronic rhinosinusitis (European Position Paper on Rhinosinusitis and Nasal Polyps (EPOS-criteria)
• Subject has a critical condition defined as: forced expiratory volume at one second < 30% and / or arterial oxygen saturation < 93% without O2-substitution; need of O2-substitution
• Subject had an ENT surgery within 6 months prior to study
• Subject participates in another clinical trial within 30 days prior to study entry