The invention relates to a use of ions or salts thereof that occur naturally in blood plasma in a dialysis method using a dialyser for substance exchange, in particular for haemodialysis or haemodiafiltration, characterised in that one or a plurality of ions or salts thereof that occur naturally in blood plasma are added to the blood to be purified before the start and/or during passage through the dialyser, such that the blood to be purified has a concentration of at least one of the said ions or salts thereof at the start of passage through the dialyser, which concentration is elevated compared to the physiological concentration of the ion or salt in blood plasma.