Folic acid

Sounds like 'FOE-lik AS-id'

Easy-to-read medicine information about folic acid – what is it, how to take folic acid safely and possible side effects.

Type of medicine Also called
  • Vitamin
  • B-Vitamin group
  • Apo-Folic Acid

What is folic acid?

  • Folic acid is the man made (synthetic) form of folate, which is a vitamin belonging to the B-group vitamins.
  • Folic acid has a number of uses:
    • It is used in pregnant women or women who are planning a pregnancy, to decrease the chance of spina bifida and other neural tube defects in the baby (see folic acid/folate in pregnancy). It is best to start taking folic acid before conception and continue until week 12 of pregnancy.  
    • Folic acid is used to treat some times of anaemia.
    • It is also used to prevent side effects in people who are prescribed methotrexate.  
  • Folic acid tablets are usually available in 800 microgram tablets and 5 milligram tablets. 


  • The dose of folic acid is different, depending on the reason you are taking it.
    • For the prevention of neural tube defects, the dose is 800 micrograms once a day.
      (400 microgram daily is usually adequate but funded tablets are available in 800 microgram strength). In women who are at higher risk of having a baby with neural tube defects, a higher dose of 5 milligrams once daily is required. Read more about folic acid in pregnancy.     
    • For anaemia caused by folic acid deficiency, the usual dose is 5 milligrams once daily.
    • In people taking methotrexate, the usual dose of folic acid is 5 milligrams once a week, on a different day to the methotrexate.   
  • Always take your folic acid exactly as your doctor has told you. The pharmacy label on your medicine will tell you how much folic acid to take, how often to take it, and any special instructions.

How to take folic acid

  • Take folic acid at the same time each day, either in the morning OR in the evening.
  • Take your folic acid tablets with a glass of water.
  • You can take folic acid with or without food.
  • If you forget to take your dose, take it as soon as you remember that day. But, if it is nearly time for your next dose, just take the next dose at the right time. Do not take double the dose.

Possible side effects

Like all medicines, folic acid can cause unwanted side effects, although not everyone gets them. Often unwanted side effects improve as your body gets used to the new medicine.

Side effects What should I do?
  • Stomach upset 
  • Feeling sick (nausea)
  • Bloating (gas in the tummy)
  • Tell your doctor if troublesome
  • Signs of an allergic reaction such as skin rashes, itching, blisters, peeling skin, swelling of the face, lips, mouth or have problems breathing
  • Tell your doctor immediately or ring HealthLine 0800 611 116

Learn more

The following links provide further information on folic acid.

New Zealand Formulary Patient Information: Folic acid

Credits: Sandra Ponen, Pharmacist. Reviewed By: Dr J Bycroft. Health Navigator NZ