When our phlegm turns yellow, we often expect the doctor to prescribe antibiotics. But he doesn’t and we are puzzled. Sometimes, we may even think the doctor is inexperienced. But he/she may be wiser than we perceive. You see, antibiotics are only effective against bacteria and not viral infections. Hence, if your upper respiratory track infection is caused by a viral infection, you may create another problem for your body if you start taking antibiotics. Check out the details in this article….