Folic acid (folicacid, FA) is a B vitamin that is available over-the-counter. Natural folic acid can be consumed through green leafy vegetables, fruits, cereals, cereals, nuts and meat, and additional supplementation is not necessary for healthy people. Folic acid is a pale yellow to orange crystalline powder, odorless and tasteless, and is divided into natural and synthetic forms. Folic acid is involved in the metabolism of amino acids and nucleotides in the body, and is closely related to cell proliferation, tissue differentiation and organism development, so it is indispensable throughout the development of the fetus, and is mainly derived from animal liver, fruits and vegetables, and nuts. The human body cannot synthesize folic acid by itself and must rely on exogenous folic acid intake to maintain its own health, so the supplementation of synthetic folic acid is of great importance. Routine supplementation of folic acid, iodine and calcium (and vitamin C for smokers) in pregnant women has been shown to be valuable. Adequate folic acid intake can also treat H hypertension. The minimum daily requirement of folic acid for a normal organism is 50ug, and the World Health Organization recommends at least 200ug/day for adults; the daily recommended amount of folic acid published in the United States is slightly higher than this standard, and no standard daily supply of folic acid has been established in China. The different doses of folic acid in different countries may be related to the specific conditions of the population in each country, and there is no uniform recommended dose at present. Further large-scale clinical validation is needed to find the optimal dose of folic acid for China [1]. The dietary guidelines recommend a maximum tolerated daily dose of 1 mg of folic acid for healthy humans; is exceeding this dose harmful to the body? Some of the current evidence suggests that excessive folic acid intake may lead to an increased risk of certain tumors, such as leukemia in children [5], asthma [6] and breast cancer in mothers, and that folic acid has a bidirectional effect on some tumors. High doses of folic acid interfere with zinc metabolism and may cause zinc deficiency. There may be other adverse effects, but they all need to be further clarified by clinical studies. Although folic acid has been used clinically for the treatment of cardiovascular and cerebrovascular disease, diabetic nephropathy, adjuvant treatment of tumors, gastrointestinal disorders, and treatment of depression, it is important to consult a physician before taking folic acid in the usual way, and the specific use of the drug should be combined with the clinical situation and guided by an interview with a physician.