Oxymetazoline nasal spray is used to relieve nasal discomfort caused by colds, allergies, and hay fever. It is also used to relieve sinus congestion and pressure. Oxymetazoline nasal spray should not be used to treat children younger than 6 years of age unless it is recommended by a doctor. Children 6 to 12 years of age should use oxymetazoline nasal spray carefully and under adult supervision. Oxymetazoline is in a class of medications called nasal decongestants. It works by narrowing the blood vessels in the nasal passages.