Pulmonary mucociliary clearance is an essential defense mechanism against bacteria and particulate matter. Mucociliary dysfunction is an important feature of obstructive lung diseases such as chronic obstructive pulmonary disease, asthma, cystic fibrosis, and bronchiectasis. This dysfunction in airway clearance is associated with accelerated loss of lung function in patients with obstructive lung disease. The involvement of the cholinergic and adrenergic neural pathways in the pathophysiology of mucus hypersecretion suggests the potential therapeutic role of bronchodilators as mucoactive agents. Although anticholinergics and adrenergic agonist bronchodilators have been routinely used, alone or in combination, to enhance mucociliary clearance in patients with obstructive lung disease, the existing evidence does not consistently show clinical effectiveness.