AIDA v4 is a freeware computer program that permits the interactive simulation of plasma insulin and blood glucose (BG) profiles for demonstration, teaching, self-learning, and research purposes. It has been made freely available on the World Wide Web as a non-commercial contribution to continuing diabetes education. In the 10 years since its internet launch over 700,000 visits have been logged at the AIDA Websites and well over 200,000 copies of the program have been downloaded. Further copies have been made available, in the past, on diskette by the system developers and from the British Diabetic Association (now called ‘Diabetes UK’), London, U.K. AIDA v4 has been described in detail in the medical/ scientific/ computing literature . It incorporates a compartmental model that describes glucose-insulin interaction in patients completely lacking endogenous insulin secretion. It contains a single extra-cellular glucose compartment into which glucose enters via both absorption from the intestine and glucose production from the liver. The AIDA v4 model] also contains separate compartments for plasma and ‘active’ insulin, the latter being responsible for glycaemic control while insulin is removed from the former by liver degradation. Full details of the AIDA v4 model are accessible from within the AIDA software package and can be viewed and printed separately via the AIDA website.