Since the introduction of inhaled quaternary anticholinergic bronchodilators, their clinical usefulness has been explored in a variety of settings. They have emerged as the inhaled bronchodilators of first choice in the management of chronic obstructive pulmonary disease (COPD). In other countries, they have also found an adjunctive role in the management of asthma. This may be best seen in the treatment of acute asthma where the combination of anticholinergic and adrenergic bronchodilators appear more effective than single-agent inhalation therapy. This finding appears consistently in large studies, whether in adult or pediatric populations. Such combination nebulizer therapy would appear to be cost effective, but further study is required.