ObjectiveTo study the anti hyperglycaemic effect of aqueous extract of the flower of Phlogacanthus thyrsiflorus Nees in streptozotocin (STZ) induced diabetic mice. MethodThe flower extract of Phlogacanthus thyrsiflorus in doses 100 and 200 mg/kg b.w was administered for 21 days and blood glucose level, serum cholesterol, liver glycogen was estimated. ResultsTreatment of the streptozotocin induced diabetic mice with the flower extract resulted in significant reduction of blood glucose level (P< 0.0001), serum cholesterol (P< 0.01) and increase in liver glycogen (P< 0.0001). ConclusionsThe results suggest that the flower extract of P.thyrsiflorus possess anti hyperglycaemic effect in streptozotocin induced diabetic mice which justifies the traditional use of this plant as ethnomedicine in treatment of diabetes.