Folic acid is a water-soluble B vitamin and is abundant in green leafy vegetables, orange juice, walnuts, peanuts, liver, kidneys, eggs and legumes. The organism needs folic acid in order to produce red blood cells in the blood, and folic acid has a very important role in cell division and its growth. In addition to folic acid deficiency can lead to fetal neural tube malformation, it can also increase the rate of fetal cleft lip and palate (hare lip), heart disease, eye, mouth, gastrointestinal tract, kidney, bone and other organ malformations, as well as increase the risk of miscarriage in pregnant women. Women of childbearing age should take 0.4 mg of folic acid daily starting 3 months before conception to prevent the occurrence of fetal neural tube malformations. The purpose of starting to take it before pregnancy is to maintain a certain level of folic acid in a woman’s body to ensure a better nutritional status of folic acid in the early embryo. According to research, it takes 4 weeks after a woman takes folic acid for the folic acid deficiency in her body to actually improve. In this way, sufficient folic acid can meet the needs of the developing nervous system during the sensitive period of fetal neural tube formation in early pregnancy, and it should be taken consistently during the sensitive period in the first trimester of pregnancy for the best preventive effect. Men should also take folic acid to ensure the quality of sperm. Studies have found that sperm quality is greatly affected when men are deficient in folic acid, due to chromosomal damage of sperm caused by abnormal nucleic acid metabolism. Women in the low incidence of neural tube abnormalities in China should also take folic acid supplements. The incidence of neural tube abnormalities in China is higher in the northern regions than in the south, and higher in rural than in urban areas. Therefore, some people believe that women in low incidence areas can get pregnant without taking folic acid. The existence of this perception is likely to be a hidden danger for the birth of children with neural tube abnormalities. According to the survey, a significant proportion of women of childbearing age in the low incidence areas still have a folic acid deficiency in their bodies. Therefore, women in low incidence areas must not be taken lightly even before pregnancy. A growing number of studies show that folic acid not only prevents fetal birth defects, but also reduces the risk of heart disease and stroke in adults.