The hypoglycemic effect of the aqueous extract of the leaves and roots of Boswellia glabra was examined using alloxan-induced diabetic rats. A single oral administration of Boswellia glabra leaf and root extract decreased the blood glucose level. The continued use of leaf and root extract for 28 days produced significant hypoglycemic effects; also there was a decrease in serum glucose, cholesterol, triglyceride, urea and creatinine levels and enzyme activities (alkaline phosphatase and glucose-6-phosphatase). Ultra structural studies of beta cell of alloxan-induced diabetic rats treated with root extract showed numerous granulated sacs in comparison to rats treated with leaf extract. Thus, rats treated with root extract showed less degranulated sacs and more number of filled secretory granules in comparison to diabetic rats. Thus the use of aqueous extract of Boswellia glabra increased the synthesis of secretory granules in the beta-cell.