A method for al of a volatile anesthetic agent from a breathing gas in a respirating apparatus includes the steps of leading at least a portion of the breathing gas through a portion of a line system in which the portion of the line system has a filter therein, cooling the breathing gas to a temperature below a temperature of the boiling point of the anesthetic agent when the breathing gas passes through the filter so as to condense the anesthetic agent out of the breathing gas, warming the breathing gas after the anesthetic agent is condensed, and leading the warmed breathing gas out of the portion of the line system back into the line system. The filter has activated carbon therein.