A retrospective study was performed on heavily pigmented pulmonary cytologic specimens from 14 hospital patients to determine the clinical features distinguishing these cases. The lavage fluid or sputum in each case was turbid and gray or black, exceeding the blackness usually seen in heavy tobacco smokers dwelling in the same urban environment. Excessive carbonaceous material was observed in the cytoplasm of pulmonary alveolar macrophages or the extracellular compartment of the smears. The latter feature is not seen in cigarette smokers. Many other pigmentary sources were ruled out, including melanin, hemosiderin, medicinal charcoal, India ink, and hematoxylin crystals. The common feature of the patients was that they recently or currently smoked the crack form of cocaine heavily; five patients also had positive toxicologic results for cocaine at admission. The authors suggest that blackened bronchoalveolar lavage fluid indicates the possibility of crack cocaine smoking and the associated sequelae, particularly when the carbonaceous material is present in the extracellular compartment.