Subjects with COPD seem to have a reduced bioavailability of Mg probably due to the use of drugs that may increase Mg losses (e.g. beta-agonists and cortisones), to a reduced dietary Mg intake, and heavy smoking. A recent study showed that the administration of endovenous or aerosol Mg sulphate with beta-agonists acutely improve maximum expiratory flow during COPD relapses as well as the prolonged treatment with endovenous sulphate Mg led to a reduction in pulmonary hyperinflation and increase in muscles involved in respiration, with a consequent clinical and instrumental improvement.