A clinical model of glucose-insulin interaction in insulin-dependent diabetes mellitus has been developed for patient and medical staff education. The model attempts to reflect the underlying (patho)physiology of insulin action and carbohydrate absorption in quantitative terms such as insulin sensitivity, volume of glucose and insulin distribution and maximal rate of gastric emptying. The model's predictions also allow a 24 h simulation of patient blood glucose profiles to be generated. A description of the model is provided and its operation illustrated by clinical case studies of insulin-treated diabetic patients. The possible use of the model as a tool for automated insulin dosage adjustment is explored.