The search for lipid laden macrophages in sputum could be a simple diagnosis method for pulmonary aspiration.To assess the usefulness of sputum lipid laden macrophages in the diagnosis of pulmonary aspiration.Sixteen children aged 0 to 4 years old, admitted with aspiration pneumonia were studied. The diagnosis was based on clinical grounds (vomiting or radiologically diagnosed swallowing abnormalities plus persistent pulmonary condensations) or radionucleide milk scanning. As controls, 6 children of 1 to 5 years old, admitted for elective tonsillectomy, were studied. Sputum was stained with Sudan III-Hematoxylin, 100 macrophages were read and each cell received a score from 0 to 4 according to the degree of staining.Lipid laden macrophages of children with aspiration pneumonia had a mean score of 150 +/- 107 (8-323) compared with those of controls that had a score of 1.3 +/- 1.5 (0-4).The study of sputum lipid laden macrophages may be a useful diagnostic method for aspiration pneumonia.