text: Essentials in saline pharmacology for nasal or respiratory hygiene in times of COVID 19 Nasal irrigation or nebulizing aerosol of isotonic or hypertonic saline is a traditional method for respiratory or nasal care A recent small study in outpatients with COVID 19 without acute respiratory distress syndrome suggests substantial symptom resolution We therefore analyzed pharmacological pharmacodynamic effects of isotonic or hypertonic saline relevant to SARS CoV 2 infection and respiratory care Mixed search method Due to its wetting properties saline achieves an improved spreading of alveolar lining fluid and has been shown to reduce bio aerosols and viral load Saline provides moisture to respiratory epithelia and gels mucus promotes ciliary beating and improves mucociliary clearance Coronaviruses and SARS CoV 2 damage ciliated epithelium in the nose and airways Saline inhibits SARS CoV 2 replication in Vero cells possible interactions involve the viral ACE2 entry mechanism chloride dependent ACE2 configuration furin and 3CLpro inhibition by NaCl and the sodium channel ENaC Saline shifts myeloperoxidase activity in epithelial or phagocytic cells to produce hypochlorous acid Clinically nasal or respiratory airway care with saline reduces symptoms of seasonal coronaviruses and other common cold viruses Its use as aerosol reduces hospitalization rates for bronchiolitis in children Preliminary data suggest symptom reduction in symptomatic COVID 19 patients if saline is initiated within 48 h of symptom onset Saline interacts at various levels relevant to nasal or respiratory hygiene nasal irrigation gargling or aerosol If used from the onset of common cold symptoms it may represent a useful add on to first line interventions for COVID 19 Formal evaluation in mild COVID 19 is desirable as to establish efficacy and optimal treatment regimens 