The present invention provides a pharmaceutical composition for dialysis wherein the decline of ionized calcium concentration in an acetate-free bicarbonate dialysate comprising no acetic acid and/or sodium acetate is controlled. The present invention further provides a dialysis agent A that comprises electrolytes, citric acid and/or citrate as pH adjuster, and/or glucose, for preparation of bicarbonate dialysates； the agent A characterized by being adjusted by citric acid and/or citrate so as to keep the electrolyte ionized calcium concentration not less than 1 mmol/L in a prepared bicarbonate dialysate. In a specific aspect of the present invention, sodium citrate is used as citrate, and the present invention provides a dialysate obtained from above.
