Bassic acid, an unsaturated triterpene acid isolated from an ethanol extract of Bumelia sartorum rootbark, elicited significant hypoglycemic activity in alloxan-diabetic rats and altered the pattern of glucose tolerance in these animals. In addition, bassic acid treatment increased significantly the glucose uptake process and glycogen synthesis in isolated rat diaphragm. Bassic acid treatment increased plasma insulin levels significantly in alloxan-diabetic rats. It is suggested that the hypoglycemia activity of bassic acid may be mediated through enhanced secretion of insulin from the pancreatic beta-cells.