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Vitamin supplement (B-group vitamin)

Folic Acid: uses, side effects & precautions

Also known as Vitamin B9, folate, folacin, pteroylglutamic acid.

This information is for general guidance only and does not constitute medical advice. Always consult a qualified healthcare professional for personal medical concerns. In an emergency, call your local emergency number.

What it is used for

  • Before and during early pregnancy to reduce the risk of neural tube defects such as spina bifida
  • Treating or preventing certain types of anaemia (folate deficiency)
  • Supporting people on some medicines that lower folate (such as methotrexate)

How it works

Folic acid is a B vitamin the body needs to make healthy red blood cells and DNA. In early pregnancy it helps the baby's brain and spinal cord develop properly.

How it is taken

Taken as a tablet, often once daily, and also found in many pregnancy multivitamins and fortified foods. The right strength differs depending on the reason for taking it, so take it exactly as your doctor, pharmacist, or the label directs.

No doses here on purpose. The right strength and schedule depend on you — only a doctor or pharmacist should set them. Always follow your prescription and the label.

Common side effects

  • Usually very well tolerated
  • Occasional mild stomach upset
  • Loss of appetite
  • Bloating

Serious effects — get help

  • Signs of a serious allergic reaction (rash, swelling of the face or throat, difficulty breathing)

If a reaction is severe — for example trouble breathing, swelling of the face or throat, or collapse — go to the nearest emergency room now or call your local emergency number. Do not wait for an online consultation.

Interactions to watch

  • Some epilepsy medicines (folic acid may affect their levels and vice versa)
  • Methotrexate and some other medicines interact with folate
  • Tell your clinician about all medicines so the right dose is chosen

Who should take care

  • If you have had a previous pregnancy affected by a neural tube defect, diabetes, a high body weight, or take certain medicines, you may need a higher strength, so ask your clinician
  • Very high doses can mask vitamin B12 deficiency, so do not exceed advised amounts without guidance
  • Start it before conception where possible for the best benefit

Frequently asked questions

When should I start taking it for pregnancy?
Ideally before you try to conceive and through the early weeks of pregnancy, as this is when it protects the baby's developing spine and brain.
Can I just eat folate-rich foods instead?
A balanced diet helps, but supplements are recommended around pregnancy because it is hard to get enough from food alone at the key time.
Is it safe to take if I am not pregnant?
Yes, it is also used for some anaemias and with certain medicines. Take the strength your clinician or the label recommends.
Do I need a higher dose?
Some people do, including those with diabetes, certain medicines, a higher body weight, or a past affected pregnancy. Ask your clinician.

Related conditions

Related medicines

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