Two girls (aged 14 and 16 years) with type I diabetes were hospitalized with blood sugar levels of 394 and 319 mg/dl as well as HbA1 levels of 14.2 and 14.1%, respectively. In the first case it was the first sign of diabetes, in the other it was the result of a metabolic dysfunction with an injection abscess after ten years of the disease. After an initial substitution with regular insulin (subcutaneously in Case 1 [1.5-1.7 IU/kg daily for 3 days; in Case 2, continuous i.v. infusion [1.3 IU/kg daily] for 58 hours, followed by injections of appropriate mixtures of short and long-acting insulin) serum glucose levels were nearly always within normal range from the third day onward. Within 6 days of normal glucose levels being established hard pitting oedema, especially of the legs, developed in both girls, associated with a weight gain of 6.1 and 7.0 kg, respectively. Renal, hepatic and cardiovascular disease having been excluded the diagnosis of insulin-induced oedema was made. Within a further two weeks the oedema had disappeared without any specific treatment.