Momordica charantia (L.) (Cucurbitaceae) commonly known as bitter gourd or karela is a medicinal plant, used in Ayurveda for treating various diseases, one of which is diabetes mellitus. In this study, various extract powders of the fresh and dried whole fruits were prepared and their blood glucose lowering effect compared by administrating them orally to diabetic rats. The aqueous extract powder of fresh unripe whole fruits at a dose of 20mg/kg body weight was found to reduce fasting blood glucose by 48%, an effect comparable to that of glibenclamide, a known synthetic drug. This extract was tested for nephrotoxicity, hepatotoxicity and biochemical parameters such as SGOT, SGPT and lipid profile. The extract did not show any signs of nephrotoxicity and hepatotoxicity as judged by histological and biochemical parameters. Thus the aqueous extract powder of Momordica charantia, an edible vegetable, appears to be a safe alternative to reducing blood glucose.