Electrolytes are salts that conduct electricity and are found in the body fluid, tissue, and blood. Examples are chloride, calcium, magnesium, sodium, and potassium. Sodium (Na+) is concentrated in the extra cellular fluid (ECF) and potassium (K+) is concentrated in the intracellular fluid (ICF). Proper balance is essential for muscle coordination, heart function, fluid absorption and excretion, nerve function, and concentration.

The kidneys regulate fluid absorption and excretion and maintain a narrow range of electrolyte fluctuation. Normally, sodium and potassium are filtered and excreted in the urine and faeces according to the body's needs. Too much or too little sodium or potassium, caused by poor diet, dehydration, medication, and disease, results in an imbalance. Too much sodium is called hypernatremia; too little is called hyponatremia. Too much potassium is called hyperkalemia; too little is called hypokalemia.