The numbers of adults with diabetes in the world is estimated to rise 300 millions in the year 2025 and this leads to increasing search for better anti-diabetic drug. The effects of the ethanol extract (1.25 g/kg) and fractions (Ethyl acetate, dichlo-romethane and butanol in the dose of 1 g/kg) of Anacardium occidentale stem bark on the blood glucose levels in streptozotocin-induced types 1 and 2 diabetic rats at different prandial states were studied. The ethanol extract of A. occidentale had no hypoglycemic effect in type 1 diabetic rats in fasting and postprandial glucose load conditions and, in type 2 diabetic rats in fasting condition. However, the extract, sig-nificantly lowered blood glucose levels in type 2 diabetic rats when fed simultane-ously with glucose. The ethyl acetate fraction showed a significant opposing effect in serum glucose rise after administration of glucose. Additionally, its dichloromethane extract also exhibited a significant reduction in serum glucose level compared to con-trol after glucose administration while its butanol fraction was devoid of this activity. These findings conclude that the active principles responsible for the antihyperglycae-mic effect might be concentrated in the ethyl acetate and dichloromethane fractions of the extract.