Allantoin, a constituent of the urinary secretions of surgical maggots and of common occurrence in plants and animals, has been found to stimulate healing, with abundant growth of healthy granulation tissue in slowly healing suppurative wounds. The excretion of this substance into the wound is doubtless one of the factors contributing to the remarkable healing effects obtained in maggot therapy, but the claim is not made that it can be substituted for maggots. Allantoin can be obtained commercially. It is bland, stable, and harmless; it has no odor and is nonstaining. The treatment is simple, painless, and inexpensive.