It is used to treat folic acid deficiency and certain types of anemia (lack of red blood cells) caused by folic acid deficiency.

Folic Acid 5mg Tablets 100's (Folic Acid)
Headache, unpleasant taste, upset stomach
Hypersensitivity
Use with caution in undiagnosed anemias. Taking folic acid might mask anemia caused by vitamin B12 deficiency and delay appropriate treatment.
Taking folic acid supplements might make seizures worse in people with seizure disorders, particularly in high doses.
Using folic acid, vitamin B6, and vitamin B12 intravenously (by IV) or by mouth might worsen narrowed arteries. Folic acid should not be used by people recovering from this procedure.
when taken by mouth appropriately during breast-feeing is likely safe.
There appears to be no risk when taking this drug during pregnancy.
Drugs such as Methotrexate, Phenobarbital , Phenytoin, Primidone, Pyrimethamine , Fosphenytoin may interact with this drug.