It is proposed a method for desulphating an exhaust gas retreatment system of an internal combustion engine comprising the steps of: the exhaust retreatment system will be checked for the presence of sulfates by measuring at least one indicative parameter, additionally or alternatively at least one of parameters related to sulfates formation in the field of exhaust gas retreatment system is detected and whether the parameters are within the sulfate formation triggering value range is determined, in the presence of sulfates, and/or the parameters are within the value range, the emissions of the internal combustion engine is adjusted by means of engine or post-engine measures so that a desulphation takes place in the exhaust gas retreatment system and/or the parameters exits the sulfates formation triggering range.