Foreign-body (dextran beads) and hypersensitivity (antigen-coupled agarose beads) lung granulomas were induced in BALB/c mice by the intratracheal injection of beads. Large granulomas developed, which reached peak intensity within 3 days and declined in size thereafter. Aqueous extracts of both granulomas contained high levels of lysosomal enzymes N-acetyl-beta-D-glucosaminidase (NAG) and lysozyme. Lysosomal enzyme activities in the extracts correlated with granuloma sizes. Dispersed granuloma cells were able to produce these enzymes. These results suggest that lysosomal enzymes may reflect the activity/size of granulomatous inflammation.