To assess the short-term tolerance of pulse methylprednisolone in patients with diabetes. Retrospective study in a national eye center. Eighty patients with type 2 diabetes, half of them also treated for hypertension, who received 3-day pulse methylprednisolone between January 1999 and December 2002 for eye disorders and were monitored according to a written protocol. Potentially serious side effects, serial blood glucose measurements, and hypoglycemic interventions during pulse therapy. Each pulse induced about 10 hours later a mean 2-fold peak increase of blood glucose. According to a 14-mmol/l (250 mg/dl) threshold glucose level for intervention, rapid insulin was required in 27 of 27 (100%) and 24 of 53 (45%) patients with glycosylated hemoglobin levels higher than 8% and up to 8%, respectively. In the latter group, patients older than 70 years had a 3-fold increased risk of requiring insulin. Significant side effects were systolic and/or diastolic blood pressure elevation > or = 180/110 mmHg (n = 6), ketosis without acidosis (n = 5), silent myocardial ischemia (n = 1), and disorientation (n = 1). All side effects were transient or controlled successfully by medical intervention. No infectious complication occurred during the treatment period. Pulse methylprednisolone is globally well tolerated in diabetic patients, but requires strict blood glucose and clinical monitoring.