Green Phlegm: Causes, Infections & When to See a Doctor

Not necessarily. The color of phlegm is not a reliable indicator of the type of infection. Green phlegm can be caused by either a bacterial or viral infection, or it may be the result of other factors, such as allergies or smoking.

The best way to determine the cause of your phlegm is to see a doctor. They can perform tests to identify the underlying infection and recommend the appropriate treatment.