Calcium often refers to calcium tablets, and methylcobalamin can be taken with calcium tablets. Methylcobalamin and calcium tablets, they work differently. Methylcobalamin is an endogenous coenzyme B12, which participates in the one-carbon unit cycle and plays an important role in the transmethylation reaction of synthesizing methionine from homocysteine. In clinical practice, it is mainly applied to patients with peripheral neuropathy and megaloblastic anemia. And calcium tablets are mainly applicable to osteoporosis, adolescents, pregnancy and postmenopausal women and other people. The two can be taken at the same time, methylcobalamin should be used in patients with peripheral neuropathy, the course of treatment is longer, while for patients with megaloblastic anemia, if the cause of the disease can be removed, the drug can be discontinued after a period of oral administration. Calcium tablets are used in patients with osteoporosis who often need long-term application. All of the above medications should be taken under the guidance of a physician to avoid adverse effects.