Causes of Phlegm in Lungs?

Phlegm is a thick liquid substance that is secreted by the mucous membrane in the windpipe or airways. This mucous like liquid is normally produced due to an infection by bacteria or virus and it always affects the lungs and the throat.

Photo Credit:

Coughing Up Mucus – Green, Yellow, Brown, White, with Blood – see the content


  1. What Causes Phlegm? –
  2. how to clear lungs of phlegm? –
  3. What Causes Fluid in Lungs? –
  4. What Causes Lung Nodules? –