Rebound congestion is a constant nasal stuffiness (congestion) that develops from the overuse of nasal sprays (or drops or gels) that contain a decongestant medicine. This type of congestion occurs even when a person is not experiencing allergies or other cold-like symptoms.

Some examples of nasal spray decongestants are oxymetazoline (such as Afrin) and phenylephrine (such as Neo-Synephrine).

Rebound congestion can develop from using a nasal decongestant more times in one day or more days than the label says. As the medicine wears off, sinus membranes swell, causing congestion. A person may respond by using more of the decongestant to make the congestion go away again. If the cycle continues, the person keeps overusing the medicine. Eventually, congestion occurs whenever they don't use the nasal decongestant.