Six patients who injected talc containing drugs intended for oral use were assessed over a period of ten or more years from the time of initiation of this habit. Despite discontinuation of the drug abuse, all developed severe respiratory disability and three died from their disease. An evolving spectrum of roentgenographic and functional patterns is considered to be virtually diagnostic of this disorder. Roentgenographically, an initial diffuse, pin-point micronodularity subsequently becomes associated with conglomerates, usually in the upper lobes, closely resembling the progressive massive fibrosis (PMF) of the pneumoconioses. The lower lobes, on the other hand, become relatively translucent, in some instances with bulla formation and the development of pneumothorax. Pulmonary function, initially with both restrictive and obstructive features, eventually becomes markedly obstructive with hyperinflation and air trapping. At this late stage, pathologic examination reveals emphysema in addition to the granulomatous inflammation and fibrosis surrounding the talc particles in the pulmonary interstitium.