<p>Calcium Polystyrene Sulfonate acts by a cumulative process throughout the gastrointestinal tract, removing potassium ions which are excreted in the feces. Calcium Polystyrene Sulfonate passes through the colon and comes into contact with fluids containing increased amounts of potassium. The result is that potassium is taken up in increasing amounts in exchange for calcium ions. The length of time Calcium Polystyrene Sulfonate remains in the body is a decisive factor in its effectiveness. For this reason oral administration is more effective than rectal administration</p>