The study was performed to compare the blood glucose lowering effect of Swietenia mahagoni seeds with an oral antidiabetic drug, rosiglitazone in experimentally induced diabetic rats. Twentyfour healthy Long Evans Norwegian strain of rats were included in the study and divided into four groups (A, B, C and D) comprising 6 rats each. Group A (control group) received standard rat food for 14 days. Diabetes was induced by a single intraperitoneal administration of alloxan 120mg/kg body weight in Group B, C and D.