Numbness of the hands and feet, cramps are common for the following reasons: First, hypocalcemia, when the blood calcium concentration is reduced, less than 2mmol/L when neuromuscular excitability increases, easy to intermittent bilateral tonic muscle spasms, the clinical manifestations of the hands and feet twitching, hands and feet fingers (toes) tip of the numbness occurs symptoms. Intravenous application of calcium gluconate and calcium chloride can quickly correct hypocalcemia, oral calcium and vitamin D can prevent hypocalcemia for a long time. Secondly, magnesium deficiency can also cause hand and foot twitching, the clinical manifestation is similar to hypocalcemia, magnesium deficiency and serum magnesium concentration is not consistent, as long as the causative factor is clear and there are clinical symptoms should be considered as magnesium deficiency, the treatment can be intravenous magnesium chloride or magnesium sulfate to correct the magnesium deficiency, it takes a long time to completely correct magnesium deficiency.