Sputum

Mucus or phlegm coughed up from the lower respiratory tract, especially the bronchi and lungs, reflecting airway or pulmonary secretion.

Causes of excessive sputum production

• Inflammatory and obstructive airway diseases

  • Chronic obstructive pulmonary disease (COPD)

  • Asthma

  • Bronchiectasis

  • Cystic fibrosis

• Infectious causes

  • Pneumonia

  • Bronchitis

  • Tuberculosis

• Irritant-related causes

  • Cigarette smoke

  • Inhaled dust

  • Air pollutants

• Allergic airway inflammation

• Post-nasal drip

• Acid reflux (GERD)

• Lung cancer