In long-term management of stable chronic obstructive pulmonary disease (COPD), a number of medications improve pulmonary function test results. The long-term clinical benefits of those drugs would seem intuitive, but there is very little strong evidence that long-term outcomes in COPD are substantially affected by those drugs. Nevertheless, symptom improvement such as dyspnea reduction is certainly strong reason to use those agents. The 2 most compelling bodies of evidence in stable COPD are for oxygen therapy in the chronically hypoxemic patient and pulmonary rehabilitation to improve exercise tolerance and dyspnea. Inhaled corticosteroids also appear to be useful in patients at risk for frequent exacerbations. In acute exacerbations, the rationale for therapy comes in part from the large body of literature regarding acute asthma therapy. Bronchodilator therapy and corticosteroids both seem to reduce the severity and the duration of exacerbations. Moreover, routine antibiotic use seems beneficial, and the role of noninvasive positive-pressure ventilation with patients suffering impending respiratory failure from acute COPD exacerbations is well supported by the literature.