The treatment of a patient with diabetes insipidus (DI) is described, and the general treatment of the syndrome is reviewed. The patient was a 16-year-old male who had experienced pain, inflammation and tenderness in the left gluteal region owing to an abcess at the site of intramuscular injection of vasopressin tannate in oil (VTO). (He had been diagnosed as having DI at age 8. Since then, he had been maintained on VTO, lypressin and posterior pituitary snuff.) After the abscess healed during hospital treatment, VTO was stopped and the patient's urinary output increased sharply; urine specific gravity and osmolarity decreased correspondingly. Three days after stopping VTO, the investigational drug, 1-deamino-8-D-arginine vasopressin (DDAVP), was begun at 10 microgram every 12 hours. The dose was eventually increased to 20 microgram every 12 hours, and the patient was discharged on this regimen which controlled his urine output, specific gravity and osmolarity. Other treatments reviewed include antidiuretic-hormone-replacement agents (vasopressin, lypressin) and drugs used to potentiate low ADH levels (chlorpropamide, clofibrate and carbamazepine).