The invention relates to a device and method for treating diabetic patients on insulin therapy. More specifically, the invention includes apparatus for infusing insulin into a patient in an amount determined by the patient's carbohydrate intake, blood glucose level, and the amount of insulin calculated to be present in the patient at the time the therapy is to be administered. In one embodiment, an insulin infusion device having an on-board processor obtains a patient's blood glucose value from a remote sensor and receives input from a user indicating their recent meal intake. The device may include an on-board food database for determining the carbohydrate content of the patient's recent meals and compare that with recent insulin deliveries into the patient to determine the insulin present in the patient prior to determining an appropriate insulin dosage.