Infiltration of eosinophil granulocytes and endothelial expression of vascular cell adhesion molecule-1 (VCAM-1) and P-selectin was investigated in biopsies of polyps and inferior turbinates from 16 patients with nasal polyps, by the use of immunohistochemical staining and stereological quantification before, during and after topical treatment with budesonide (Rhinocort Turbuhaler). Before glucocorticoid treatment a higher density of eosinophil profiles (p < 0.005), making up a larger proportion of the total cellular infiltrate (p < 0.0005), was found in the polyps compared with the inferior turbinates. Endothelial VCAM-1 expression was higher in polyps than in inferior turbinates (p < 0.005), in contrast with the expression of P-selectin, which was more frequently expressed in the inferior turbinates (p < 0.05). Topical glucocorticoid treatment reduced the density of eosinophil profiles (p < 0.05) and the endothelial expression of VCAM-1 (p < 0.007) and P-selectin (p < 0.02) in polyps. Eosinophil counts and VCAM-1 expression returned to pre-treatment levels 8 weeks after discontinuation of budesonide treatment. The observed reduction in endothelial expression of cellular adhesion molecules may interfere with cellular recruitment in nasal polyps and thus contribute to the known anti-inflammatory effect of glucocorticoid in nasal polyposis.