We studied the effect of disodium cromoglycate (DSCG) used as a therapeutic drug for the treatment of bronchial asthma on infiltration of inflammatory cells into the bronchial mucosa and on the expression of adhesion molecules in asthmatic patients. Biopsies of the bronchial mucosa of 9 patients with atopic asthma were performed before and after the administration of an aerosol containing DSCG (8 mg/day). Staining with anti-EG2 antibody was made on the tissues obtained to determine the number of eosinophils, with anti-NP57 antibody to determine the number of neutrophils, with anti-AA1 antibody for mast cells, with anti-CD4, -CD8, -CD3 for T lymphocytes, and with anti-CD68 antibody for macrophages. Another staining was made to examine the expression of adhesion molecules including intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1) and endothelial leukocyte adhesion molecule-1 (ELAM-1) on the vascular endothelium and to determine the presence of P-selection. Moreover, the intensity of the expression of ICAM-1 on the bronchial epithelium was investigated. The number of eosinophils, mast cells, T lymphocytes and macrophages were significantly decreased, and the expression of ICAM-1, VCAM-1 and ELAM-1 were significantly inhibited by the administration of DSCG. There were significant correlations between ICAM-1 and the number of T lymphocytes, and between VCAM-1 and the number of eosinophils. These results suggest that DSCG inhibits the expression of adhesion molecules as an anti-inflammatory action, and decreases the number of inflammatory cells in the airways of asthmatic patients.