(HealthDay News) -- Coughing serves an important purpose -- to help you expel mucus, microbes and other foreign particles from your respiratory tract.
This helps protect the lungs from infection and inflammation, Harvard Medical School says. A cough becomes chronic if it lingers for at least three to eight weeks, the school adds.
Its list of reasons for a chronic cough includes:
How to Decide When You're Too Sick to Work
Whooping Cough Vaccine Effectiveness Fades With Time: Study
