The dosage of folic acid is usually one capsule once a day. The size of folic acid is usually 0.4mg per capsule. Folic acid is mainly used to prevent fetal neural tube defects, prevent anemia in pregnant women, prevent congenital malformations in fetuses, promote placental development, and prevent pre-eclampsia in pregnant women. Therefore, folic acid supplementation is generally advocated for the first trimester of pregnancy as well as the second trimester of pregnancy. Because of the long-term use of folic acid and the fact that folic acid itself has a certain degree of gastrointestinal stimulation, it should be taken after meals as much as possible.