The treatment for anemia depends on its cause:

• Iron deficiency anemia is treated with iron supplements (Feratab, Fer-Iron, Slow-FE) to help increase iron stores. If the deficiency is caused by internal bleeding, its source needs to be located and treated as well.
• Vitamin-deficiency anemias are treated with supplements of the missing vitamins (folate, B6, B12). For pernicious anemia — a common cause of B12 deficiency — injections of B12 are required (usually for life) because people with this condition cannot absorb B12 from their diet.
• Anemia caused by chronic disease is best treated by focusing on managing the underlying chronic disease. If anemia symptoms become severe, a blood transfusion may be required to provide more oxygen-carrying capacity. Alternatively, injections of the hormone erythropoietin (which stimulates the bone marrow to make more red blood cells) may help. 
• Aplastic anemia can be temporary or chronic. If it is temporary, it can be treated with blood transfusions. If the bone marrow has failed and cannot recover the ability to make RBCs, a bone marrow transplant may be required.
• Leukemia or other blood cancers may be treated with chemotherapy or may require a bone marrow transplant.
• Hemolytic anemias may be treated with medications that suppress the immune system such as corticosteroids or gamma globulin. Underlying blood disorders should also be treated and any medications that might be contributing to the problem should be adjusted. In some cases, the spleen can become so laden with large numbers of damaged RBCs that it may need to be removed.
• Sickle cell anemia is caused by a genetic mutation and so it can’t be cured. Treatment to reduce the symptoms includes supplemental oxygen, blood transfusions, pain-relievers, folic acid supplements, and antibiotics. In some cases, a bone marrow transplant can help.  A drug called hydroxyurea (Droxia, Hydrea) may also be used to treat sickle cell anemia in adults.