Saline solutions used in nasal irrigation reduce inflammation through osmosis. Swelling is a major factor in sinus dysfunction. Removal of mucus plays an important role in sinus health, and nasal irrigation facilitates this by flushing out thickened mucus that cannot be handled by the cilia .   improving mucociliary clearance and also removing infected material.  Damage to the mucociliary transport system is an important factor in the development of sinonasal diseases, leading to a stasis of mucus.  The numerous proteins found in nasal mucus include inflammatory mediators , defensins and many whose function is not understood.