|When you have a respiratory infection, do you surreptitiously check your tissue to see what colour your phlegm is? You’re not alone. It’s a commonly held belief that light-coloured or clear phlegm means you aren’t very sick, while yellow or green phlegm means a bacterial infection and a round of antibiotics.
While many doctors and patients use phlegm colour as a barometer for bacteria, it’s not an accurate indicator. In fact, treating a respiratory infection with antibiotics often does more harm than good. Phlegm is a fact of life.
Phlegm is one of several forms of mucus that are present in everyone’s body. Mucus keeps various tissues moist and protects the body against foreign objects. In the respiratory system, it keeps dust and other matter out of the lungs. Mucus also contains antibodies that kill pathogens like bacteria and viruses.
When inflamed by allergens or disease, the respiratory system produces a larger amount of nasal mucus as well as phlegm, called sputum when it is expelled through the mouth by coughing. This is a normal part of the immune response — the phlegm traps allergens, bacteria and viruses.
The excess mucus may start clear and then and then thicken and change colour as the body attacks pathogens with an enzyme produced by white blood cells, the foot soldiers of the immune system. This germ-killing enzyme, myeloperoxidase, contains iron that gives phlegm and nasal mucus a yellowish or greenish shade when present in large amounts.
The doctor doesn’t deny that excessive phlegm and other symptoms are uncomfortable, but suggests natural ways to manage them while your immune system tackles their root cause. Many respiratory infections are self-limiting, meaning that they run their course and go away without the need for harsh antibiotics.Dr. Barbara Smith