There are currently no clear contraindications to folic acid. As a water-soluble vitamin, folic acid is widely available in food and can be easily obtained. Even if folic acid is used in excess, it will be excreted in the urine and will not accumulate in the body, so it is relatively safe and has no clear contraindications. However, the use of folic acid has the following precautions: large doses affect the absorption of zinc, the need for zinc supplementation. Different people have different needs for folic acid, so you need to consult your doctor for the exact dose. Patients with pernicious anemia and suspected vitamin B₁₂ deficiency, especially with neurological symptoms, cannot use folic acid alone and need to supplement vitamin B₁₂ at the same time. If you are purchasing folic acid medication, you need to use it under your doctor’s supervision and not without authorization.