Mometasone is used to prevent and treat seasonal and year-round allergy symptoms (such as stuffy/runny nose, itching, and sneezing). It is also used to treat certain growths in the nose (nasal polyps). Mometasone belongs to a class of drugs known as corticosteroids. It works by reducing swelling (inflammation) in the nasal passages. OTHER This section contains uses of this drug that are not listed in the approved US professional labeling for the drug but that may be prescribed by your health care professional. Use this drug for a condition that is listed in this section only if it has been so prescribed by your health care professional. This medication may also be used to treat sinus inflammation (sinusitis). It should be used with an antibiotic if sinusitis is caused by a bacterial infection.