Syzygium cumini is commonly known as insulin plant in India. Consumption of leaves of this plant are believed to lower blood glucose level in healthy normal and diabetic individuals. The present study was planned to evaluate the effect of the leaves of syzygium cumini leaves on dexamethasone induced hyperglycemic rats. MaleWistar rats (n=6) were treated with 10mg/kg of dexamethasone subcutaneously for 20 days from 11th day to 20 days. Different groups received 100mg/kg plant extract in distill water and glibenclamide 500µg/kg per orally on plasma blood glucose level, serum total cholesterol, triglyceride level, HDL, LDL and Serum VLDL were observed. Dexamethasone caused an increase blood glucose level, serum total cholesterol, serum triglyceride level, Serum HDL ,Serum LDL and Serum VLD and compare with normal control[ **P<0.01]. In the dexamethasone model 100mg/kg p.o. of Ethanolic extract of syzygium cumini leaf showed significant decrease in blood glucose level, serum total cholesterol , serum triglyceride level, Serum HDL ,Serum LDL and Serum VLDL when compared to dexamethasone control[l.**P<0.01]. The study results concluded Syzygium cumini proved to be effective in treatment of Type-II Diabetes mellitus owing to its ability to decrease insulin resistance.