Hypermagnesemia is condition that more than the normal serum magnesium concentration (general magnesium in blood more than 1.05mmoL/L). Most of hypermagnesemia is renal dysfunction caused by a decrease in excretion. The same as hypomagnesemia, serum magnesium concentrations, is not a reliable indicator of magnesium increased because 25% of serum magnesium and protein binding, which does not exert some physiological effects of magnesium; magnesium ions mainly in the cells, so when the body content of magnesium increase in serum magnesium in normal range. However, under normal circumstances the body hypermagnesemia and magnesium increase the degree of consensus. As the kidneys of sodium ions, potassium ions, bicarbonate ions must have delayed the role of regulation, the renal regulation of magnesium did not obvious role to play quickly, so a large number of intravenous application of magnesium preparations, do not pay attention to monitoring, can also be serious hypermagnesemia. If the merger of renal dysfunction, the regulating role of the kidneys severely weakened, while prone to hypermagnesemia.