Patients with Parkinson's disease are at risk for pulmonary complications as a consequence of both the underlying disease pathology and the side effects of medication. Degeneration of the substantia nigra and subsequent loss of dopaminergic neurons may produce changes in ventilatory parameters. Upper airway obstruction and chest wall restriction are both common, and both may respond to levodopa. However, therapy for Parkinson's may also contribute to pulmonary morbidity. Overtreatment with levodopa causes respiratory dyskinesia that may be difficult to differentiate from complications of the disease itself. Therapy with ergot derivatives may cause pleuropulmonary fibrosis. Pneumonia resulting from the respiratory complications remains a significant cause of morbidity and mortality in Parkinson's disease.