The study investigated whether ethanolic propolis extract would exhibit an anti-diabetic effect in rats. The animals were divided into four groups of five rats each. Diabetic rats received 30% or 15% propolis extract at a dosage of 0.5 ml/100 g for 4 weeks. Data for the diabetic groups treated with 30% and 15% propolis showed a decrease in blood sugar levels from 393 +/- 192.7 to 154 +/- 28.0 mg/dl and from 386 +/- 141.1 to 331.5 +/- 123.74 mg/dl, respectively. Compared with the diabetic control group, an improvement was observed in both groups treated with propolis at the pancreatic, hepatic, and renal tissue levels. Antioxidant capacity, phenolic analysis, and the inhibition of alpha-amylase and alpha-glucosidase were also tested using the propolis samples to support in vivo data. Chrysin and caffeic acid phenyl ester were the dominant phenolics. The IC50 results for alpha-amylase (0.62 +/- 0.00 mu g/ml) and alpha-glucosidase (40.40 +/- 0.09 mu g/ml) were also encouraging.