Diabetes mellitus is a syndrome with disordered metabolism and inappropriate hyperglycaemia due to either a deficiency of insulin secretion or to a combination of insulin resistance and inadequate insulin secretion to compensate. Commiphora kerstingii is a tree of 10m high that grows in savanna from Togo to Nigeria, and on to Central African Republic, and it belongs to the family Burseraceae. In Zaria Nigeria, the stem-bark is used traditionally for managing diabetes mellitus. Phytochemical screening was carried out in accordance with the standard protocol as described by Trease and Evans and the oral LD50 of the extract in rats was conducted according to the method described by Lorke. Glucose, nicotine and dexamethasone were used to in induce hyperglycaemia. The dose of 400 mg/kg of the extract significantly (p < 0.02) prevented an elevation in blood glucose at the 2nd and 3rd hours in the oral glucose load model. In the nicotine-induced hyperglycaemic model 100 mg dose of the extract significantly (p < 0.05) lowered the BGL only at the 5th hour, while 200 mg/kg and 400mg/kg doses lowered the BGL at the 4th and the 5th hours. Dexamethasone was administered subcutaneously at a dose of 10 mg/kg/day for ten days consecutively. All doses of the extract used significantly (p < 0.05) lowered the Blood Glucose Level when compared with the group that was administered dexamethasone alone on all the days monitored.