The paper deals with the results of the investigations so far, which have pointed out an inverse correlation between drinking-water hardness and morbidity and mortality rates of cardiovascular diseases. Among the water hardness elements special attention has been given to magnesium, as its deficiency in organism is likely to present an important risk factor for cardiovascular disorders. The options of preventive measures in this field are discussed-adding of magnesium to soft drinking-waters, salt enriched with magnesium, consumption of natural mineral waters, or Mg supplements.