Folic acid, also called vitamin B9, is a water-soluble vitamin that is relatively important for promoting the maturation of red blood cells in bone marrow, as well as the growth and development of the fetus. Meanwhile, proper supplementation of folic acid by pregnant women can also prevent eclampsia during pregnancy. Folic acid is one of the essential vitamins to maintain the healthy growth and development of the human body, mainly absorbed in the small intestine, glucose and vitamin C in the body can promote the absorption of folic acid in the body. Folic acid plays an important role in the growth, differentiation, and repair of the body’s cells. If there is a deficiency of folic acid, it may lead to malformations in fetal development, as well as underdevelopment of the fetal neural tube. In addition, folic acid also promotes the maturation of megaloblastic red blood cells in the bone marrow. If the body is deficient in folic acid, megaloblastic anemia may occur, so folic acid can be used to prevent megaloblastic anemia, and can also prevent low birth weight, cleft lip and palate, heart defects, anencephaly, and spina bifida in the fetus. Folic acid supplementation in adults can lower homocysteine levels, which is useful for improving hypertension and preventing cardiovascular diseases.