Over-the-counter nasal sprays available without prescriptions, known as vasoconstrictors, act within minutes against a blocked nose. The active ingredient causes the blood vessels to constrict for a time, allowing the air to circulate. Use of these sprays is recommended for the short-term relief of symptoms when suffering from regular cold.

However, using these sprays for longer than a week can cause serious damage to the mucous membranes, resulting in the development of chronic nasal congestion, which in turn requires ever higher doses of the spray to be kept under control. This is a vicious circle which soon leads to dependency.

This dependency and the severe damage to the mucous membranes require lengthy and extensive treatment, until patients are weaned off the nasal spray and their noses returned to normal healthy function. In rare cases, it may be impossible for the mucous membranes to recover; the essential functions of the nose such as recognizing smells or cleaning the breathing air are lost forever.