Magnesium (Mg 2+) is the 2nd most abundant intracellular cation, which participates in various enzymatic reactions; there by regulating vital biological functions. Magnesium (Mg 2+) can regulate several cations, including sodium, potassium, and calcium; it consequently maintains physiological functions like impulse conduction, blood pressure, heart rhythm, and muscle contraction. But, it doesn’t get much attention in account with its functions, making it a “Forgotten cation”. Like other cations, maintenance of the normal physiological level of Mg 2+ is important. Its deficiency is associated with various diseases, which point out to the importance of Mg 2+ as a drug. The roles of Mg 2+ such as natural calcium antagonist, glutamate NMDA receptor blocker, vasodilator, antioxidant and anti-inflammatory agent are responsible for its therapeutic benefits. Various salts of Mg 2+ are currently in clinical use, but their application is limited. This review collates all the possible mechanisms behind the behavior of magnesium as a drug at different disease conditions with clinical shreds of evidence.