How does the saltwater solution helps to cure cold and cough? Ever wondered when we gargle with salt water how it helps to reduce cough. Salt water has osmotic properties, when the solution passes near mucus cells it draws water from the mucus cells effectively thinning the mucus layer. ( The salt concentration in the solution causes to create difference so water draws out of mucus) Salt water also soothes the throat. When taken as nasal spray or drop it does the same action to reduce cold symptoms.