The thought of mucus disturbs many people. Mucus is beneficial as the first defense of the airways. The mucus lining traps inhaled particles and allows them to be cleared from the airway by cilia and cough. The mucus layer also prevents dehydration and desiccation of the airway surface and provides a nutrient milieu for the ciliated epithelium. Mucus can also be quite bad. Airway mucus retention due to hypersecretion or poor mucus clearance is a characteristic of many airway diseases including cystic fibrosis, chronic bronchitis, bronchiectasis, and asthma. Mucus retention is thought to lead to airway obstruction, atelectasis, and tissue destruction by entrapping inflammatory mediators. It promotes microbial.
