Universal drinking water and beverages containing moderate to high levels of magnesium (10–100 ppm) could potentially prevent 4.5 million heart disease and stroke deaths per year, worldwide. This potential is calculated with 2010 global mortality figures combined with a recent quantification of water-magnesium’s inverse association with heart disease and stroke mortality. The modern processed food diet, low in magnesium and spreading globally, makes this well-researched potential of drinking-water magnesium worth serious consideration, especially in areas where insufficient dietary intake of magnesium is prevalent.