kidney patients have problems excreting urine( a waste product ) from the body. If you are on peritoneal dialysis or hemodialysis you are relying on the PD solution or the dialysis machine to clean/pull the toxins out of your circulatory system. Potassium (K+) already is not eliminated through urine from your bladder so it builds up in your system. Orange Juice is high in potassium (K+) so it is not recommended for dialysis patients. On the hemodialysis floor at my hospital we do not give Orange Juice to dialysis patients for just this reason. A proper balance between Sodium, Calcium and Potassium is necessary for proper cardiac function Higher than normal potassium levels can lead to heart arrhythmias .