Method for operating a water-conducting domestic appliance (11, 211, 311), wherein the domestic appliance (11, 211, 311) comprises: - a treatment chamber (15, 215, 315), - a supply system containing marker substances and enzymes, - a nozzle device for applying the marker substances to objects in the treatment chamber (15, 215, 315), the nozzle device being connected to the supply system, - means for introducing water into the treatment chamber (15, 215, 315) and a water supply therefor, - heating means for the water, - a pump in the water supply, - detection means designed for an optical detection method for detecting dirt marked with the marker substances, with the steps: a) marker substances are applied to objects to be cleaned in the treatment chamber (15, 215, 315) by means of the means for introducing water into the treatment chamber (15, 215, 315), preferably only on some of the objects in the treatment chamber (15, 215, 315) or only in a specific area of the treatment chamber (15, 215, 315), b) an optical detection method is used to detect whether the marker substances have marked dirt on the objects to be cleaned, whereby the dirt is detected in such a way, characterised by the step: c) if dirt has been detected, the following two steps E) and S) are carried out in an arbitrary order: E) applying enzymes by means of the means for introducing water into the treatment chamber (15, 215, 315) to objects or areas on which dirt has been detected, S) creating suitable local conditions for the enzymes to be effective on the dirt in terms of temperature and/or humidity of the objects, wherein the enzymes are designed to remove the detected dirt, wherein suitable local conditions for the effectiveness of the enzymes are created by introducing tempered or heated air and/or water into the treatment chamber (15, 215, 315), wherein air and/or water are applied either generally or over a large area or specifically to areas or objects in which dirt has been detected and/or into which the enzymes have been applied. - a treatment chamber (15, 215, 315), - a supply system containing marker substances and enzymes, - a nozzle device for applying the marker substances to objects in the treatment chamber (15, 215, 315), the nozzle device being connected to the supply system, - means for introducing water into the treatment chamber (15, 215, 315) and a water supply therefor, - heating means for the water, - a pump in the water supply, - detection means designed for an optical detection method for detecting dirt marked with the marker substances, with the steps: a) marker substances are applied to objects to be cleaned in the treatment chamber (15, 215, 315) by means of the means for introducing water into the treatment chamber (15, 215, 315), preferably only on some of the objects in the treatment chamber (15, 215, 315) or only in a specific area of the treatment chamber (15, 215, 315), b) an optical detection method is used to detect whether the marker substances have marked dirt on the objects to be cleaned, whereby the dirt is detected in such a way, a) marker substances are applied to objects to be cleaned in the treatment chamber (15, 215, 315) by means of the means for introducing water into the treatment chamber (15, 215, 315), preferably only on some of the objects in the treatment chamber (15, 215, 315) or only in a specific area of the treatment chamber (15, 215, 315), b) an optical detection method is used to detect whether the marker substances have marked dirt on the objects to be cleaned, whereby the dirt is detected in such a way, characterised by the step: c) if dirt has been detected, the following two steps E) and S) are carried out in an arbitrary order: E) applying enzymes by means of the means for introducing water into the treatment chamber (15, 215, 315) to objects or areas on which dirt has been detected, S) creating suitable local conditions for the enzymes to be effective on the dirt in terms of temperature and/or humidity of the objects, wherein the enzymes are designed to remove the detected dirt, wherein suitable local conditions for the effectiveness of the enzymes are created by introducing tempered or heated air and/or water into the treatment chamber (15, 215, 315), wherein air and/or water are applied either generally or over a large area or specifically to areas or objects in which dirt has been detected and/or into which the enzymes have been applied. E) applying enzymes by means of the means for introducing water into the treatment chamber (15, 215, 315) to objects or areas on which dirt has been detected, S) creating suitable local conditions for the enzymes to be effective on the dirt in terms of temperature and/or humidity of the objects, wherein the enzymes are designed to remove the detected dirt, wherein suitable local conditions for the effectiveness of the enzymes are created by introducing tempered or heated air and/or water into the treatment chamber (15, 215, 315), wherein air and/or water are applied either generally or over a large area or specifically to areas or objects in which dirt has been detected and/or into which the enzymes have been applied.