Vitamin B12, also known as cobalamin, is a multi ring compound containing trivalent cobalt. Four reduced pyrrole rings are linked together to form a large gluline ring (similar to porphyrin), which is the only vitamin containing metal elements. Vitamin B12 is a red crystalline powder, odorless and tasteless. It is soluble in water, insoluble in ethanol, insoluble in acetone, chloroform and ether. [7] It is most stable under the condition of pH 4.5~5.0 weak acid. It is decomposed in strong acid (pH<2) or alkaline solution, and may be damaged to some extent in case of heat. Higher animals and plants cannot produce Vitamin B12, and Vitamin B12 in nature is synthesized by microorganisms. Vitamin B12 is the only vitamin that can be absorbed only with the help of Parietal cell secretion [8] (endogenous factor). It is involved in the production of bone marrow red blood cells, preventing Pernicious anemia and brain nerve damage