The artificial beta cell is a Glucose Controlled Insulin (and dextrose) Infusion System (GCIIS) for maintaining normoglycemia in diabetic conditions and other disturbances of metabolism. The insulin and dextrose infusion rates are calculated by a microcomputer according to the static glucose concentration (proportional control) and to its rate of change (dynamic control). The algorithms controlling the computer can be adapted to the subjects' requirements. It has already been shown, that the artificial beta cell is able to maintain blood sugar values in diabetics within physiological ranges during the course of the day. In our present study we examined the response of the artificial beta cell using a 100 gm oral glucose load in severe diabetics. The first type of control algorithms applied effected a rather small initial insulin infusion following OGTT in 8 juvenile diabetics connected with the artificial beta cell. The glucose responses thus obtained were similar to latent diabetes. In contrast, when the computer was controlled by the second type of algorithms with a more responsive dynamic control and a consequently higher initial insulin infusion, in one diabetic OGTT was fully normalized, whereas an improvement was achieved in another diabetic patient. Furthermore it was shown that control algorithms must be varied individually, depending on residual beta cell function and glucose regulatory mechanisms.