Coughing is a natural reflex of the body designed to clear the airways of mucus, irritants, and foreign particles. However, it can be frustrating and concerning when that persistent cough just won't quit. A cough that won't quit should never be ignored, whether it's due to a common cold, allergies, or something more serious. Why Can’t I Stop Coughing? A chronic or persistent cough, lasting for three weeks or more, can ...