The present invention relates to a composition for preventing or treating diabetes mellitus using a 4-component mixture of putrescine, glucosamine, nicotinamide, and a STAT3 inhibitor. It has been confirmed that blood glucose is stably regulated when a compound of the 4-component mixture according to the present invention is injected into the caudal vein of a diabetes mellitus-induced mouse. The compound can be practically and usefully used as a therapeutic agent for diabetes mellitus patients and patients exposed to diabetes mellitus risk.