Emphysema is one of the components of chronic obstructive pulmonary disease beside the bronchial, vascular and systemic parts. The pathogenesis involves an inflammatory process (macrophages, neutrophiles and lymphocytes), but also an imbalance between proteases-anti-proteases and the oxidative stress by the formation of oxygen radicals. On the therapeutic level, these physiopathological pathways are the rational basis to the progressive use of antioxidants (mainly N-acetylcysteine) or, for the moment at an experimental level, of anti-proteases (inhibitors of serine proteases, cysteine proteases and the matrix metalloproteases). To reach the secondary lobule, site of the emphysema, the inhaled future treatments will have to be constituted of small particles, as in cigarette smoke, in order to distribute into the most homogeneous way the affected lung.