Surgery may be undertaken for the complications of diabetes mellitus (DM), such as coronary artery disease, peripheral vascular disease and renal failure, or the diabetes may be unrelated to the surgical procedure. The aims of metabolic management perioperatively are to avoid hypoglycaemia, excessive hyperglycaemia, and minimise lipolysis and proteolysis by the provision of exogenous glucose and insulin. In the virtual absence of clinical studies in general surgery, and considering the basic biological data on the harmful effects of hyperglycaemia, it is reasonable to recommend that blood glucose should be maintained in the range of 6-10 mmol l-1. There is general agreement that all type 1 diabetic patients should be managed with an intravenous glucose-insulin-potassium (GIK) infusion for inpatient surgery. It is common practice to administer the glucose infusion in the GIK regimen at 100-125 ml h-1.