This study was conducted to investigate the median lethal dose level and the hypoglycemic effect of Eugenia caryophyllata Myrtaceae essential oil extract in healthy and diabetic mice. Extract of Eugenia caryophyllata Myrtaceae, glibenclamide (as a reference group) and physiologic saline (control group) were administrated to the healthy and diabet oc-cured mice with alloxan. Blood was taken before treatment the first, second, third, fourth and 24^th hours, from the vena coccygea of mice. Blood glucose levels were measured. When compared with physiologic saline group it was observed that Eugenia caryophyllata Myrtaceae extract decreased blood glucose values significantly in a diabet occured mice with alloxan in the second and 24^th hours, this effect was not observed in the first and fourth hour. Glibenclamide decreased blood glucose values significantly in the first, second, fourth and 24^th hours. There was not a significant difference of blood glucose values measurements between Eugenia caryophyllata Myrtaceae and glibenclamide. In the healthy controls, blood glucose level decreased less then other groups only at the 4^th hour. It was observed that the essential oil extract of Eugenia caryophyllata Myrtaceae has significantly hypoglycemic effect in the second and 24^th hours when compared with physiologic saline group with was used as a control. It was not showed that hypoglycemic effect the extract of Eugenia caryophyllata Myrtaceae in the first and fourth hours. The lethal dose 50 of the extract of Eugenia caryophyllata Myrtaceae was determinated 0.613 ml/kg body weight.