anemia has many causes. The length of treatment will depend on the cause of the anemia. Most hematologists suggest that a trial of 3 months of iron therapy and then retesting is in order. Many physicians will retest in 6 weeks to see if there is any improvement. But it is very important to follow with a physician to be sure the cause is found and the treatment is working.

It all depends on the cause. If it is the lack of iron or a vitamin it may be as simple as replacing the missing element. If due to marrow damage it may be a much longer treatment.