A device for regulating the concentration of glucose in the blood of a diabetes patient includes a measuring component for measuring the concentration, a pump component for selectively introducing glucagon, or glucose instead, or insulin into the body of the patient, for instance by way of at least one hypodermic needle to be inserted into the body of the patient; and a control component which receives signals from the measuring component which are representative of the concentration and which control the pump component on the basis of at least one reference value for the concentration pre-entered into the control component and a program; wherein the device is embodied such that the measuring component and the pump component can be in substantially permanent contact with the bodily fluid or the blood of a patient.