Folic acid tablets should not be taken by people who have experienced severe gastrointestinal symptoms (nausea, bloating, etc.) or allergic reactions to medications while taking folic acid in the past. Folic acid is a vitamin that plays an important role in DNA synthesis in human cells. When the human body is deficient in folic acid, cellular DNA synthesis will be significantly affected, which may lead to the occurrence of megaloblastic anemia, and need to take oral folic acid tablets in time for treatment. Folic acid tablets are safer drugs with fewer adverse reactions. Oral folic acid tablets seldom cause allergic reactions, such as itching of the skin, and seldom cause gastrointestinal symptoms such as nausea and abdominal distension. It is not recommended to continue taking folic acid tablets if the patient has had previous allergic reactions, gastrointestinal symptoms and other adverse reactions. When folic acid tablets are used for the treatment of megaloblastic anemia, folic acid supplementation alone is not recommended for treatment, regardless of whether the patient has a vitamin B₁₂ deficiency or not; vitamin B₁₂ should be supplemented at the same time. This is because the increase in bone marrow hematopoiesis after folic acid supplementation leads to an increase in vitamin B₁₂ consumption, which may cause patients to develop symptoms of neurological damage such as numbness of the hands and feet, numbness of the tongue, or aggravation of pre-existing symptoms. It is recommended that patients take folic acid tablets under the guidance of a physician and do not adjust the dose of the drug privately.