For the treatment of megaloblastic anemia, Folic acid is given by mouth in doses of 5 mg for 4 months; up to 15 mg daily may be necessary in malabsorption states. Continued administration of folic acid 5 mg every 1 to 7 days by mouth may be necessary in chronic haemolytic states. In the prophylaxis of megaloblastic anemia of pregnancy, the usual dose is 0.2 to 0.5 mg daily. And 4 or 5 mg daily in prevention of neural tube defect starting before pregnancy and continued through the first trimester. For other women of child-bearing potential the dose is 0.4 mg daily.