Like all medicines, folic acid can cause side effects in some people. But many people have no side effects or only minor ones.
Common side effects
There are things you can do to help cope if you get these side effects of folic acid:
Feeling sick (nausea)
Take folic acid with, or just after, a meal or snack to help with feeling sick.
If you're pregnant, it could be morning sickness that's making you feel sick. If you have pregnancy sickness, try taking folic acid at a time of day when you feel better.
Loss of appetite
Eat when you'd usually expect to be hungry. If it helps, eat smaller meals more often than usual. Have nutritious snacks that are high in calories and protein, such as dried fruit and nuts.
Bloating or wind
It might help to eat smaller and more frequent meals, eat and drink slowly, and exercise regularly. If the symptoms get worse, contact your doctor straight away.
Speak to a doctor or pharmacist if the advice on how to cope does not help and a side effect is still bothering you or does not go away.
Serious allergic reaction
In rare cases, folic acid can cause a serious allergic reaction (anaphylaxis).
Immediate action required: Call 999 now if:
- your lips, mouth, throat or tongue suddenly become swollen
- you're breathing very fast or struggling to breathe (you may become very wheezy or feel like you're choking or gasping for air)
- your throat feels tight or you're struggling to swallow
- your skin, tongue or lips turn blue, grey or pale (if you have black or brown skin, this may be easier to see on the palms of your hands or soles of your feet)
- you suddenly become very confused, drowsy or dizzy
- someone faints and cannot be woken up
- a child is limp, floppy or not responding like they normally do (their head may fall to the side, backwards or forwards, or they may find it difficult to lift their head or focus on your face)
You or the person who's unwell may also have a rash that's swollen, raised, itchy, blistered or peeling.
These can be signs of a serious allergic reaction and may need immediate treatment in hospital.
Do not drive yourself to A&E.
The person you speak to at 999 will give you advice about what to do.
Other side effects
These are not all the side effects of folic acid. For a full list, see the leaflet inside your medicine packet.
Reporting side effects
You can report any suspected side effect using the Yellow Card safety scheme.
Visit the Yellow Card website for more information about reporting side effects.