Proteolysis and oxidation are processes which play a central role in the pathogenesis of emphysema. Hereditary factors, including α1-antitrypsin deficiency, and environmental exposures, such as to cigarette smoke, coal dust and bacteria, are associated with a high risk for the development of emphysema through their interactions with proteolytic and oxidative processes within the lung. Because of the key roles of oxidation and proteolysis, reasonable strategies for the prevention of lung destruction in high-risk individuals include such therapeutic interventions as augmentation of lung levels of α1-antitrypsin and the administration of antioxidants