Side effects of too much folic acid include abdominal cramps, nausea, diarrhea, gas, skin rash, sleep disorders, seizures and behavior changes, such as irritability, excitability and confusion, according to WebMD. Most adults are able to tolerate 400 micrograms of folic acid daily.
Folic acid, a B vitamin, is found in leafy vegetables, beans, yeast, mushrooms and certain fruits and meats, WebMD states. Federal law also requires that it be added to many processes foods, such as cereals, flours, breads, pastas, baked goods and crackers. There are several medical uses for folic acid, including treating anemia and kidney disease, preventing miscarriage and spinal bifida, and reducing serious side effects of methotrexate, a cancer-fighting drug.