Safety and side effects

When taken by mouth at suggested doses, folic acid is likely safe.

Taking high doses of folic acid by mouth can cause:

• A bitter taste in the mouth.
• Nausea.
• Loose stools.
• Confusion.
• Irritability.
• Trouble sleeping.
• Stomach cramps.

People with allergies might have a reaction to folic acid supplements. Warning signs of an allergic reaction include:

• Skin rash.
• Itching.
• Skin color changes, such as purple or brown depending on your skin color.
• Difficulty breathing.

If you take too much folic acid, it comes out of the body in urine.

When a person takes a high amount of a folic acid supplement, it can be hard to know if the person has enough vitamin B-12. Taking folic acid supplements can help correct low blood counts, but it won't repair nerve damage from not having enough vitamin B-12. Taking a supplement that has 100% of the Daily Value of both folic acid and vitamin B-12 can help prevent this issue.