ABSTRACTUmbelliferone (7-hydroxycoumarin), a derivative of coumarin, is benzopyrone in nature, and it is present in the fruits of golden apple (Aegle marmelos Correa) and bitter orange (Citrus aurantium). The present study was designed with the objective of evaluating the effect of umbelliferone (UMB) on glycemic control and glycoprotein components in the plasma and tissues (liver, kidney, heart, and brain) of streptozotocin (STZ)-induced diabetic rats. Adult male albino rats of Wistar strain, weighing 180 to 200 g, were induced diabetes by administration of STZ (40 mg/kg b.w.) intraperitoneally. The normal and diabetic rats were treated with UMB dissolved in 10% dimethyl sulfoxide (DMSO) for 45 days. In our study, diabetic rats had decreased plasma insulin and elevated blood glucose, sialic acid, total hoxoses, fucose, and hexosamines in the plasma and tissues. Treatment with UMB brought the levels of glucose, sialic acid, total hoxoses, fucose, and hexosamines to near-normal level. Thus, our results show that treatment with UMB has improved glycemic control and thereby reduced the formation of glycoprotein components. This leads to the normalization of circulatory and tissue sialic acid, fucose, hexoses, and hexosamines in STZ-diabetic rats, which reflects a protective effect of UMB from the risk of diabetic complications.