ABSTRACT
The precise interaction between airflow obstruction, reduced mucociliary clearance, smoking, hypersecretion and infection, and their individual and interactive importance to respiratory morbidity and subsequent mortality in separate conditions remains at best debatable and at worst a mystery Detailed research into sputum over the past two decades has greatly increased our depth and breadth of knowledge. Let us hope that continuing studies in this field will lead, perhaps through adaptation of the quantity or quality of respiratory mucus, to new and more successful therapeutic strategies.
