hi, i ve been having green coloured mucus for years now. I ve had it since i was 8; and as i aged, it got progressively worse in colour and thickness. Fortunately, I do have days where I don t have the mucus and go through the day relatively able to breathe through my nose. But those days are few and far between. What do you think could be causing it? Allergies? My dad is a heavy smoker as well, and he smokes in the house. I realize that my nose gets really stuffed up when I m home, yet, it s about the same as when i m outside. What could be the possible reasons behind my green mucus?