an anesthesia device supplying a first and second anesthetic in a quantitatively settable , controlled manner . a data processing unit with a corresponding display is set up for determining the current concentrations in the plasma or at the site of action from continuously supplied data on the quantities of the anesthetics administered with a module for a pharmacokinetic compartment model calculation and for storing these concentration values . concentration data is predicted for at least one point in time in the future . an action module provides a curve of an anesthesia action parameter as a function of the concentrations of the anesthetics . a display module displays a diagram showing the sequence of concentration of the first or second anesthetic , and the predicted concentration .