AIDA is a prototype computer system that incorporates a model of glucose-insulin interaction in type I diabetes mellitus alongside a knowledge-based system to make glycaemic predictions and to generate insulin dosage adjustment advice. The model attempts to reflect the underlying (patho)physiology of insulin action and carbohydrate absorption in quantitative terms. The prototype is intended to be used as a decision support system by clinical personnel in the context of day-to-day management of insulin-dependent diabetic patients. It is designed for use during consultations, as a simulator of patient response following changed insulin and dietary regimen and as a system for providing education on planning insulin therapy. Joe Daniels is a 41-year-old, 70-kg, male insulin-dependent diabetic patient who was diagnosed as being diabetic in 1972, at the age of 22. Joe recently found that he was having hypoglycaemic symptoms. Using self-monitoring blood glucose equipment, glycaemic levels below 3.0 mmol/l were recorded at least once a week, while hyperglycaemic readings (> 16 mmol/l) were observed two to three times per week. Joe came into hospital to have his glycaemic control improved, as doctors were concerned about the risks of him suffering a serious hypoglycaemic attack. Using some of the data collected by Joe while in hospital, we will demonstrate how AIDA might be applied either in a clinical setting to provide therapeutic advice or in an educational setting to interactively teach diabetic patients about their diabetes and educate them to adjust their own insulin injections and diet.