--Cold & Flu.....and ME--

Coughing is the body's way of removing foreign material or mucus from the lungs and upper airway passages or of reacting to an irritated airway. Coughs have distinctive traits you can learn to recognize. A cough is only a symptom, not a disease, and often the importance of your cough can be determined only when other symptoms are evaluated.
~
Productive coughs
A productive cough produces phlegm or mucus (sputum). The mucus may have drained down the back of the throat from the nose or sinuses (postnasal drainage) or may have come up from the lungs. A productive cough generally should not be suppressed; it clears mucus from the lungs. There are many causes of a productive cough, such as:

• Viral illnesses. It is normal to have a productive cough when you have a common cold. Coughing is often triggered by mucus that drains down the back of the throat.
• Infections. An infection of the lungs or upper airway passages can cause a cough. A productive cough may be a symptom of pneumonia, bronchitis, sinusitis, or tuberculosis.
• Chronic lung disease. A productive cough could be a sign that a disease such as chronic obstructive pulmonary disease (COPD) is getting worse or that you have an infection.
• Stomach acid backing up into the esophagus. This type of coughing may be a symptom of gastroesophageal reflux disease (GERD) and may awaken you from sleep.
• Nasal discharge draining down the back of the throat (postnasal drip syndrome). This can cause a productive cough or the feeling that you constantly need to clear your throat. Experts disagree about whether a postnasal drip or the viral illness that caused it is responsible for the cough.
• Smoking or other tobacco use. Productive coughs in a person who smokes or uses other forms of tobacco is often a sign of lung damage or irritation of the throat or esophagus.

~

~http://www.webmd.com/cold-and-flu/tc/coughs-topic-overview