What is folic acid?

Folic acid is a naturally occurring substance that is important for the formation of red and white blood cells. Folic acid is present in foods such as dried beans, peas, lentils, oranges, whole-wheat products, liver, asparagus, beets, broccoli, brussels sprouts, and spinach.

As a medication, folic acid is used to treat folic acid deficiency and megaloblastic anemia caused by folic acid deficiency.

Folic acid may also be used for purposes other than those listed in this medication guide.


Folic acid should not be taken to treat undiagnosed anemia. Folic acid may hide the symptoms of pernicious anemia, leading to neurologic damage. Treatment of anemia during folic acid therapy may also require vitamin B12.

Folic acid is in the FDA pregnancy category A. This means that it is safe to take folic acid during pregnancy. In fact, increased amounts of folic acid are recommended during pregnancy to reduce the risk that a folic acid deficiency will cause complications. Talk to your doctor about taking folic acid during pregnancy.

It is safe to use folic acid during breast-feeding. Talk to your doctor about taking this medication if you are breast-feeding a baby.

There are no restrictions on food, beverages, or activities while you are taking folic acid, unless your doctor directs otherwise.

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A folic acid overdose is unlikely to threaten life. Call an emergency room or poison control center for advice.

Symptoms of a folic acid overdose are not known.

Take the missed dose as soon as you remember. However, if it is almost time for your next dose, skip the dose you missed, and take only your next regularly scheduled dose. Do not take a double dose of this medication unless otherwise directed by your doctor.

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Side effects

Side effects from folic acid are not common.

Stop taking folic acid and seek emergency medical treatment if you experience an allergic reaction (difficulty breathing; closing of your throat; swelling of your lips, tongue, or face; or hives).

Continue taking folic acid and talk to your doctor if you experience any of the following less serious side effects, which have occurred with large doses of folic acid:

  • nausea,
  • decreased appetite,
  • abdominal distention,
  • flatulence,
  • bitter or bad taste,
  • insomnia, or
  • difficulty concentrating.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088. You may report side effects to FDA at 1-800-FDA-1088.

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Large doses of folic acid may decrease the effects of phenytoin (Dilantin). Your doctor may need to adjust your dose of phenytoin to prevent seizures during treatment with folic acid.

Drugs other than those listed here may also interact with folic acid. Talk to your doctor and pharmacist before taking any prescription or over-the-counter medicines.

Other Names

FA-8, Folacin-800, and folic acid

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Every effort has been made to ensure that the information provided by Cerner Multum, Inc. ('Multum') is accurate, up-to-date, and complete, but no guarantee is made to that effect. Drug information contained herein may be time sensitive. Multum information has been compiled for use by healthcare practitioners and consumers in the United States and therefore Multum does not warrant that uses outside of the United States are appropriate, unless specifically indicated otherwise. Multum's drug information does not endorse drugs, diagnose patients or recommend therapy. Multum's drug information is an informational resource designed to assist licensed healthcare practitioners in caring for their patients and/or to serve consumers viewing this service as a supplement to, and not a substitute for, the expertise, skill, knowledge and judgment of healthcare practitioners. The absence of a warning for a given drug or drug combination in no way should be construed to indicate that the drug or drug combination is safe, effective or appropriate for any given patient. Multum does not assume any responsibility for any aspect of healthcare administered with the aid of information Multum provides. The information contained herein is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. If you have questions about the drugs you are taking, check with your doctor, nurse or pharmacist.

Copyright 1996-2004 Cerner Multum, Inc. Version 2.05. Revision date 8/23/04

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