Nasal irrigation is the practice of flushing the nasal cavity with a sterile solution. The solution may contain antibiotics. Nasal irrigation is used to clear infected sinuses or may be performed after surgery to the nose region. It may be performed by adding antibiotics to the solution to treat nasal polyps, nasal septal deviation, allergic nasal inflammation, chronic sinus infection, and swollen mucous membranes. Irrigation may also be used to treat long-term users of inhalants, such as illicit drugs (cocaine), or occupational toxins, like paint fumes, sawdust, pesticides, or coal dust.

Nasal irrigation should not be performed on people who have frequent nosebleeds; have recently had nasal surgery; or whose gag reflex is impaired, as fluid may enter the windpipe.

Nasal irrigation can be performed by the patient at home, or by a medical professional. A forced-flow instrument, such as a syringe, is filled with a warm saline solution. The solution can be commercially prepared (Ayr, NaSal) or can be prepared by the patient, using one half teaspoon salt with each eight ounces of warm water. Occasionally, antibiotics are added to the solution, to kill bacteria and aid healing of irritated membrane. The syringe is then directed into the nostril. The irrigation solution loosens encrusted material in the nasal passage, and drainage takes place through the nose. The patient leans over a catch basin during irrigation, into which the debris flows. Irrigation continues until all debris is cleared from the passage. Nasal irrigation can be performed up to twice daily, unless the irrigation irritates the mucous membrane.

To help prevent complications, the patient is instructed not to open his or her mouth or swallow during the procedure. Opening the mouth or swallowing could cause infectious material to move from the nasal passage into the sinuses or the ear.

Complications of nasal irrigation include irritation of the nasal passage due to extreme temperature of the irrigation solution. Rarely, irrigation fluid may enter the windpipe. This most often occurs in people with a poor gag reflex.