Most of the cases of phlegm and cough after the cold are due to the infection of the upper respiratory tract, which has entered our airway through the throat. So generally speaking, the pre-cold treatment is not in place, one may be hard to resist or during the cold did not avoid eating fried, greasy, or taste too heavy, fresh, spicy things, such as these things are harmful to the cold medicine to work. For example, the general cold medicine is to clear heat, and eat spicy, fried hot things, the cold medicine to offset the cold, cold medicine can not work. Another in the cold if you eat too much taste, the throat is actually a gateway, heat stuck in the gateway into the lungs, it is like a sentry, if you eat too much taste sentry can not hold the disease into the airway, after a into the airway, the airway is mucous membrane, will be a lot of mucus generation, the dirty things that come in as far as possible to find a way to hold out. Because the mucous membrane once inflammation will swell, and then the secretion will greatly increase, there will also be a lot of phlegm, cough.