ABSTRACTThe present studies emphasize the investigation on ethanolic extract of Memecylon kollimalayanum. (Family- Melastomataceae) leaves for its anti-diabetic activity in animal model. Alloxan induced diabetes model was used for the study. The pharmacological and acute toxicity studies of ethanolic extract was performed by following, OECD-423 guidelines (Acute toxic class method). No mortality or acute toxicity was observed upto 2000mg/kg of body weight. The standardized doses of 250, 500, 1000 and 2500 mg /kg 1 body weight of the extract were administered orally to normal and diabetic rats in order to define its hypo-glycemic potential. Results The Biological dose of extract Memecylon kollimalayanum dose was selected 200mg/kg and 400mg/kg in this dose possessed significant antidiabetic activity. This study shows that flavanoids present in this extract may be possibly responsible for the antidiabetic activities respectively. Histopathological studies on isolated pancreas revealed that ethanolic extract of Memecylon kollimalayanum   reversed the changes which produced due to diabetes caused by Alloxan. The normal pattern of histology of pancreas was observed. Keywords: Ethanolic Extract, OECD-423 guidelines