What your doctor will give you are prenatal vitamins.. Which includes folic acid.. But you can always take folic acid from the store, it wont' do you any harm.

Folic acid is a water soluable vitamin, which means, even if you take both prenatal vit that contain folic acid and a separate pill that's only folic acid, if your body only needs 400mg of folic, than that's all your body will absorb, the rest will be discarded in your urine.

Kiss-me...Forgive me I forget, are you trying to concieve? And how old are you??