Why do they trade cough supressors?
1.Cough is the body's natural selfdefense.
2.Do medical doctors prescribe thesis towels?
Answer: Coughs can not only spread more germs than needed, but can also be inconvenient, uncomfortable or sore, and can cause ulcer in the esophagus and stomach if severe adequate.
While coughs are a natural response to some piece of food or phlegm or something stuck contained by the esophagus, chronic coughing is caused by a disease/sickness and isn't needed.
On top of that, the body's self-defense isn't other a good entry. Ever heard of autoimmune diseases, where on earth the body's own antibodies (protective forces) kills the lenient on accident by attacking forceful cells instead of a virus?
Of course M.D.'s don't prescribe quality newspaper towels - they can be bought over the counter from Wal-Mart. :-)