What does green flem mean?

I believe what is being referred to here as "flem" is really phlegm, or the thick mucus that comes from the mouth. Green phlegm can mean a sign of an infection such as a cold or flu, bronchitis, or some kind of allergic reaction. Usually any kind of colored phlegm can be a sign of an infection so it is advisable to visit a health center or doctor if one has persistent colored phlegm for prolonged periods of time.