Saline solution treats nasal passages that are irritated by allergies or colds, notes Drugs.com. Dr. Anne Marie Helmenstine for About.com reports that a saline solution can also be used as a mouthwash and to disinfect piercings or other wounds.
WebMD notes that a saline solution dissolves mucus accumulation in the throat. A saline application also reduces the amount of crust that forms in the sinus cavities. Studies show that a saline solution lowers inflammation to the mucus membranes. Regular use of the solution may also cleanse the nasal passages of bacteria and reduce chances of postnasal drip.
WebMD adds that saline spray and rinses can remove pollen from the nasal lining and are a good source of moisture during the dry winter. A nasal steroid spray is a suitable option for treating allergies, but doctors recommend using a regular nasal spray to rid the passages of bacteria and other debris before applying more powerful solutions. Saline nasal solutions also maintain the cilia, which are hairs in the nose that add humidity to the lungs and prevent bacteria from penetrating the cells. Saline sprays may also treat sinusitis and rhinitis if the cilia are kept healthy.
Helmenstine mentions that a saline solution can also be used for sterile rinsing. Salt should be placed in warm water if it is going to be used as a mouthwash, and baking soda can be added to the mixture.