Phenylephrine is a decongestant that shrinks blood vessels in the nasal passages. Dilated blood vessels can cause nasal congestion (stuffy nose).

Phenylephrine nasal is used to treat nasal congestion and sinus pressure caused by allergies, the common cold, or the flu. Phenylephrine may be used to treat congestion of the tubes that drain fluid from your inner ears, called the eustachian tubes.