The present study was investigated the activity of aqueous extract from Cinnamomum cassia bark on the blood glucose levels in healthy and diabetic rats induced by Streptozotcin (STZ). In healthy rats the blood glucose levels were slightly decreased after six hoursof single oral administration with dose (25 mg/kg) of body wight, as well as four weeks after twice daily repeated oral administration of aqueous extract of Cinnamomum cassia bark. In streptozotocin induced diabetic rats we absorved high significant decreased (p<0.05) in blood glucose levels, after four weeks of oral administration of aqueous extract (25 mg /kg ).And blood glucose levels seems to be normal after the period of treatment .Glibenclamide used as standard drug to comparative aqueous extract in lowering blood glucose level .Giving healthy rats lead to significant increasing p<0.05 in body weight ,whereas diabetic rats induced by streptozotocin showing significant decreased p<0.05 in body weight . Also in this study was determination extract activity on lipid profile, liver enzymes (ALT,AST), Creatinine and Urea in the serum of experimental rats. Result showing significant increasing p<0.05 in Cholesterol, Triglyceride, HDL-C ,VLDL-C concentration in diabetic rats and after treatment with aqueous extract significant decreasing was happened for all of the parameters .In additional Non significant differences were observed in Creatinine ,Urea and insulin concentration in healthy and streptozotocin induced diabetic rats .This is approved that there are no side effect of aqueous extract on kidney and insulin secretion or concentration. In thisstudy our conclusion that the aqueous extract of Cinnamomum cassia bark working as antihyperglycemic without any changed in insulin concentration
