Prolonged administration of saline does not cause hyperkalemia. Saline consists of a sterile aqueous solution of 0.9% sodium chloride with an osmolality similar to that of human blood, a sodium content similar to that of plasma, and a slightly higher chlorine content than that of plasma. Potassium ions are normally absent from saline if no other agents are artificially added. Hyperkalemia after fluid infusion may be caused by improper management of hypokalemia, by the intravenous administration of large amounts of potassium salts, or by the patient being given large amounts of stored blood resulting in hyperkalemia. Generally prolonged saline infusion does not cause hyperkalemia. In addition, hyperkalemia can be caused by decreased potassium excretion due to renal potassium excretion dysfunction in patients with renal failure or saline corticosteroid deficiency, as well as by prolonged use of large amounts of potassium-retaining diuretics. Patients should seek medical advice promptly for any discomfort and should not use drugs blindly on their own.