Vitamin B12 is the only water soluble essential vitamins containing metal ion. It mainly affects the hematopoietic system and the nervous system when Vitamin B12 deficiency. Through the research on its physiological function, vitamin B12 is a kind of human body essential nutrients, participate in a variety of metabolism in the body, can effectively prevent malignant anemia, senile dementia depression and other diseases, and plays an important role in maintaining human health.