Infusion pump for the delivery of a quantity of a medicament to the body of a patient determinable by means of an electronic control device, the pump being provided with a computer for calculating the maximum permitted administration quantity for each case as a function of the previously delivered quantity and with a blocking device for preventing further administration of the medicament on exceeding a predetermined, permitted maximum value, in which the computer determines the quantity or concentration of the active substance in the body of the patient resulting from the delivered medicament quantity and its breaking down in the body and compares it with the predetermined maximum value.