Oxymetazoline is a topical nasal decongestant commonly used to relieve nasal congestion and sinus pressure associated with the common cold. It works by constricting blood vessels in the nasal passages, which rapidly reduces swelling and improves airflow. Relief is often felt within minutes, making it useful for short-term symptom control, especially at night. Because prolonged use can cause rebound congestion, oxymetazoline should be used no more than 3 days in a row. It treats congestion symptoms only and does not address the underlying viral infection.