Methylmalonic acidemia(MMA) is one of the common diseases in hereditary organic acid metabolism disorder. The disorder is mainly treated by using vitamin B₁₂ which comes in various forms.The use of the methylcobalamin and adenosylcobalamin in China cannot meet the needs of children with MMA. Parenteral use of hydroxocobalamin of high concentration has significant advantages in the treatment of MMA. But, the accessibility to hydroxocobalamin is challenging now.Through the supervision and adjustment of hydroxocobalamin, we explored the strategy of using the drugs. Meanwhile, we are considering the oral use of the hydroxocobalamin as supplement to treatment. Solving the challenges of the hydrococobalamin is helpful to meet the treatment of MMA and to provide a new possibility for the use of medication for rare diseases. The improvement in policy and supervision measures will facilitate the development, involvement, and production of hydroxocobalamin, so that the patients will have a good chance of access to the treatment.