Background: In traditional medicine, leaves of eucalyptus (Eucalyptus globules L.) possess interesting biological behavior, such as antioxidation, antibacterial and antiviral activities. The aim of thgis study was to evaluate hypoglycemic effect of alcoholic extract of eucalyptus (Eucalyptus globulus L.) leaves in healthy and diabetic rats.
Materials and methods: In this experimental study, the effects of oral administration of 0.05, 0.1, 0.2 and 0.4 g/kg body weight of eucalyptus leaves alcoholic extract for 21 days on the glucose and insulin levels in healthy and streptozotocin-induced diabetic rats were evaluated. A comparison was made between the effect of the alcoholic extract and a known antidiabetic drug, glibenclamide (600 mg/kg body weight).
 Results: The results showed that orally administration of the eucalyptus alcoholic extract decreased significantly the serum glucose levels, whereas it increased serum insulin in diabetic but not in normal rats (p<0.05). The extract could not change the level of serum glucose and insulin in normal rats significantly. The hypoglycemic effect of the extract was similar to that observed by glibenclamide.
Conclusion: The eucalyptus alcoholic extract can serve as a good adjuvant in the present armamentarium of antidiabetic drugs. Further biochemical and pharmacological investigations should be carried out to elucidate in details the mechanism of action of this plant.