[Pneumothorax due to drug inhalation].

Two cases of spontaneous pneumothorax after repeated inhalation of cocaine and forced aspiration of marijuana smoke, respectively, are presented. The absence of pneumomediastinum and associated subcutaneous emphysema in both cases is stressed. Inspiratory manipulations against resistance are assessed as potential etiological factors, although the coexistence of other pneumothorax predisposing factors seems to be necessary.