Phlegm that is coughed up from the lungs signals the presence of an infection or disease of the lower respiratory system, says Everyday Health. A physician must evaluate the material to determine its cause and whether antibiotic or alternative treatment is needed.
Phlegm or sputum is the mucus-like material that is ejected during an infection, according to an article published in the Lung journal. Phlegm traps bacteria, inflammatory cells and other debris present in the airway. This differs from nasal mucus, which is the thin and often runny material that is drained or blown from the nasal sinuses, adds Everyday Health.
Phlegm that is green or yellow in color indicates the presence of a bacterial infection and is treated with antibiotics, notes Reuters. Phlegm that is white or clear in color is either caused by a viral infection, such as the virus for the common cold, or it is caused by another source. In this case, antibiotic treatment is not recommended, as viruses do not respond to antibiotics.
Sputum that is stained with blood indicates a more severe disease, such as tuberculosis and lung cancer, informs MedicineNet. A broncoscopy procedure allows physicians to view and collect a sample of the sputum to determine its cause, explains Healthline.