Folic acid can prevent fetal malformations when reasonably supplemented in early pregnancy, but if taken in excess it may cause side effects, including neurological damage, zinc deficiency, gastrointestinal reactions, induced convulsions, etc. It is necessary to pay attention to the dosage and it is recommended to take it under the guidance of a doctor. 1. neurological damage: taking too many folic acid tablets can mask the early manifestation of vitamin B12 deficiency and lead to neurological damage; 2. zinc deficiency: pregnant women Taking too much folic acid can affect the digestion and absorption of zinc. And zinc has an important role in fetal development, and zinc deficiency can delay fetal development; 3. Gastrointestinal reactions: long-term use of folic acid can lead to abdominal distension, dizziness, nausea and vomiting, resulting in a series of gastrointestinal reactions; 4. Induction of convulsions: folic acid may have certain effects on convulsive drugs, and if patients taking convulsive drugs take large amounts of folic acid at the same time, it may cause convulsions; 5. Yellowing: taking too much folic acid may have the symptom of discharging light yellow urine. Therefore, it is best to take folic acid reasonably under the guidance of a doctor and not in excess to avoid side effects. Pregnant women can also supplement folic acid through food, such as animal liver, kidney, poultry meat, eggs, as well as fresh vegetables and fruits, beans and cereals.