Many times people come in with lingering cough or congestion, long after their acute sickness is over.  Here is one of the main culprits: dairy.  Dairy keeps the inflammatory mucous response continuing well after a person no longer has a cold virus.  I recommend people stop all dairy, including yogurt and butter, while they have a cold and for a few days after, until all the phlegm has cleared.   A very simple to implement tip!

If allergies are bothering you, check out this post