Folic acid is used to treat anemia resulting from an increase in the size of megaloblastic red blood cells, which is associated with folic acid deficiency and to prevent neural tube defects, such as spina bifida, in the fetus during pregnancy, as folic acid deficiency is one of the main factors for these birth defects and to reduce the side effects resulting from the use of methotrexate, which is one of the drugs used in the treatment of cancer.
Folic acid is used to enhance brain function, as folic acid deficiency is associated with decreased mental abilities and an increased risk of dementia and Alzheimer's disease.