Intensified insulin therapy is usually carried out either with multiple subcutaneous insulin injections (ICT: intensified conventional therapy) or with continuous subcutaneous insulin infusion (CSII) by minipumps. For two years we have been studying two matched groups of type I diabetic patients, treated with 3 daily insulin injections (ICT) and with CSII ( Microjet , Miles), respectively. Blood glucose control, as assessed by integrated mean blood glucose (MBG), was similar in both groups, but a better metabolic stability ('M' index of Schlichtkrull ) was evident in the CSII group. From the 24-hour profiles of plasma 'free' IRI and metabolites (glucose, beta-OH-butyrate, lactate, pyruvate, alanine), both the hepatic and peripheral underinsulinization and related metabolic alterations were still evident in both groups of patients. The number of hypoglycaemic episodes, recorded by home blood glucose monitoring, was similar in both groups of patients, while the perception of symptomatic hypoglycaemia seemed to be reduced in the patients treated with CSII.