Clinical and experimental data demonstrate that hormonal factors are involved in magnesium regulation. It is possible that the parathyroid hormone could play an important role in the maintenance of normal calcium and magnesium concentrations. The action of other hormones in magnesium metabolism appears to be an indirect response to factors such as calcium concentration or changes in volume. Alterations of the magnesium concentrations are important for the intracellular potassium, sodium and calcium content. Magnesium deficiency appears to lower intracellular potassium and to increase intracellular sodium and calcium concentrations. Therefore, magnesium is essential to avoid cardiovascular diseases (acute myocardial infarction, arrhythmias, hypertension) and to restore cellular potassium concentrations.