This study was designed to determine the effects of methanolic extracts of Annona muricata
(Linn) on the blood glucose level of streptozotocin-induced diabetic Wistar rats. Thirty adult Wistar rats were randomly assigned into three groups (A, B and C) of ten rats each. Group A was the control, Group B was untreated hyperglycemic group and group C was A. muricata
-treated group. Hyperglycemia was induced in groups B and C by a single intra-peritoneal injection of 80mg/kg streptozotocin dissolved in 0.1M citrate buffer. The control group was intraperitoneally injected with equivalent volume of citrate buffer and all the animals were monitored for four weeks. Daily intra peritoneal injection of 100mg/kg A. muricata
was administered to group C rats for two weeks and the animals were monitored for another two weeks. The data obtained were analyzed with descriptive and inferential statistics. The result showed a mean body weight of 206 ± 7.74g, 173.29±5.13g and 197 ± 5.62g respectively for the control, untreated diabetic and A. muricata
-treated diabetic group, and a mean blood glucose concentration of 3.78 ± 0.190 mmol/L, 21.64 ± 2.229mmol/L and 4.22 ± 0.151mmol/L for the control, untreated diabetic and treated diabetic groups respectively. A significant difference exists between the blood glucose concentrations of treated and untreated hyperglycemic groups of rats.The result of this study demonstrated that A. muricata
possesses anti-hyperglycemic activities.