The results of this study suggest that an altered expression pattern of sulfated glycosaminoglycans (GAGs) in nasal polyp may not function as a charge restriction barrier for vascular permeability, contributing to the leakage of protein and fluid. Sulfated GAGs are found on the vascular endothelial surface and in the extracellular matrix in various tissues and organs, suggesting that these materials constitute a negatively charged screen restricting the movement of circulating plasma molecules. This study was designed to elucidate the distributional characteristics of sulfated GAGs in normal human nasal mucosa and nasal polyp in order to understand their roles in the formation of nasal polyp. The expression and localization of sulfated GAGs in normal human nasal mucosa and nasal polyp were detected light microscopically with the histochemical method using poly-L-lysine-conjugated colloidal gold followed by silver enhancement. Sulfated GAGs in normal human nasal mucosa were distributed in the epithelial layer, vascular endothelial surface, submucosal gland and extracellular matrix. In nasal polyp, intense staining was also seen in the glandular structure and epithelial layer. However, the vascular endothelium and extracellular matrix exhibited either a weak reaction or no reaction.