Magnesium sulphate (MS) is molecule with bronchodilatory properties and has been successfully used for treatment of acute exacerbation of asthma .The use of magnesium sulphate has also been evaluated for treatment of acute exacerbation of chronic obstructive pulmonary disease (copd).There is conflicting results of different studies evaluating the efficiency of Magnesium sulphate .The aim of this study is to review the findings of those studies and to answer the question if there is any rationale for use of magnesium sulphate as an adjuvant therapy in acute exacerbation of copd