Having green phlegm typically means your body is fighting an infection. Causes can include bronchitis, pneumonia, sinusitis, or cystic fibrosis.

Coughing up yellow or green phlegm This usually means your body is fighting off some sort of infection. People often develop yellow phlegm in the early stages, and it turns green the longer the infection lingers. Possible health conditions related to coughing up yellow or green phlegm include: Sinusitis. Bronchitis. Pneumonia. Cystic fibrosis.

Green phlegm indicates a widespread and robust immune response. The white blood cells, germs, and other cells and proteins that the body produces during the immune response give the phlegm its green color. While phlegm of this color can point to an infection, a person does not always need antibiotics.

Green phlegm is typically associated with infection. According to the American Lung Association, pneumonia can cause a cough that produces green, yellow, or bloody phlegm. Pink or rust-colored phlegm that contains blood can indicate the presence of a serious medical issue such as tuberculosis or an abscess.