Diabetes mellitus is a chronic disorder caused by inherited and/or acquired deficiency in production of insulin by the pancreas or by the ineffectiveness of the insulin produced by the target cells. Most conventional therapies for the management of type II diabetes include oral hypoglycemic drugs, exercise, diet and physical intervention therapies such as Acupuncture. Insulin is used in the management of type 1 diabetes mellitus. Insulin and oral hypoglycemic drugs are expensive and have numerous side effects. Through ages different communities have used medicinal herbs for diabetes mellitus management. Today herbal remedies are gaining popularity because the efficacy of conventional medicine is on the wane. This study was designed to bioscreen aqueous leaf extracts of Caesalpinia volkensii for its hypoglycemic potential. Its in vivo toxicity was also evaluated. Ethnobotanical and pharmacological information on the plant was gathered from the local traditional herbal practitioner. The three tested dose levels (50, 100, and 150mg/kg body weight) lowered blood glucose levels appreciably. Phytochemical screening results show that the aqueous extract has phytochemicals associated with antidiabetic activity. The analysis of trace metal composition of the aqueous extracts showed that it contained Manganese, Iron, Copper, Zinc, Magnesium, Molybdenum, Chromium and Vanadium, all of which aid in lowering blood glucose levels. Preliminary in vivo histopathological analysis established that the extracts had no toxic effects on the organs and tissues. The study has established that the aqueous leaf extracts of Caesalpinia volkensii are effective and safe for management of diabetes mellitus.