In cases where oral iron has either proven ineffective, would be too slow (for example, pre-operatively) or where absorption is impeded (for example in cases of inflammation), parenteral iron can be used. The body can absorb up to 6 mg iron daily from the gastrointestinal tract. In many cases the patient has a deficit of over 1,000 mg of iron which would require several months to replace. This can be given concurrently with erythropoietin to ensure sufficient iron for increased rates of erythropoiesis.

Treatments for anemia depend on cause and severity. Vitamin supplements given orally (folic acid or vitamin B) or intramuscularly (vitamin B) will replace specific deficiencies.

Definitive therapy depends on the cause:

- Symptomatic treatment can be given by blood transfusion, if there is marked anemia. A positive Coombs test is a relative contraindication to transfuse the patient. In cold hemolytic anemia there is advantage in transfuse warmed blood

- In severe immune-related hemolytic anemia, steroid therapy is sometimes necessary.

- In steroid resistant cases, consideration can be given to rituximab or addition of an immunosuppressant ( azathioprine, cyclophosphamide)

- Association of methylprednisolone and intravenous immunoglobulin can control hemolysis in acute severe cases

- Sometimes splenectomy can be helpful where extravascular hemolysis, or hereditary spherocytosis, is predominant (i.e., most of the red blood cells are being removed by the spleen).

Corticosteroids can be used to treat anemia in DBA. In a large study of 225 patients, 82% initially responded to this therapy, although many side effects were noted. Some patients remained responsive to steroids, while efficacy waned in others. Blood transfusions can also be used to treat severe anemia in DBA. Periods of remission may occur, during which transfusions and steroid treatments are not required. Bone marrow transplantation (BMT) can cure hematological aspects of DBA. This option may be considered when patients become transfusion-dependent because frequent transfusions can lead to iron overloading and organ damage. However, adverse events from BMTs may exceed those from iron overloading. A 2007 study showed the efficacy of leucine and isoleucine supplementation in one patient. Larger studies are being conducted.

No complications arise from macrocytosis itself and a prognosis will be determined from its cause.

Mild macrocytosis is a common finding associated with rapid blood restoration or production, since in general, "fresh" or newly produced red cells (reticulocytes) are larger than the mean (average) size, due to slow shrinkage of normal cells over a normal red cell circulating lifetime. Thus, chronic obstructive pulmonary disease (COPD), in which red cells are rapidly produced in response to low oxygen levels in the blood, often produces mild macrocytosis. Also, rapid blood replacement from the marrow after a traumatic blood loss, or rapid red blood cell turnover from rapid hemolysis (G6PD deficiency), also often produces mild macrocytosis in the associated anemia.

Macrocytosis is the enlargement of red blood cells with near-constant hemoglobin concentration, and is defined by a mean corpuscular volume (MCV) of greater than 100 femtolitres (the precise criterion varies between laboratories). The enlarged erythrocytes are called macrocytes or megalocytes (both words have roots meaning "big cell").

Round macrocytes which are not codocytes are produced in chronic alcoholism (which produces a mild macrocytosis even in the absence of vitamin deficiency), apparently as a direct toxic effect of alcohol specifically on the bone marrow.

Anisocytosis is a medical term meaning that a patient's red blood cells are of unequal size. This is commonly found in anemia and other blood conditions. False diagnostic flagging may be triggered by an elevated WBC count, agglutinated RBCs, RBC fragments, giant platelets or platelet clumps. In addition, it is a characteristic feature of bovine blood.

The red cell distribution width (RDW) is a measurement of anisocytosis and is calculated as a coefficient of variation of the distribution of RBC volumes divided by the mean corpuscular volume (MCV)

Acquired hemolytic anemia may be caused by immune-mediated causes, drugs and other miscellaneous causes.

- Immune-mediated causes could include transient factors as in "Mycoplasma pneumoniae" infection (cold agglutinin disease) or permanent factors as in autoimmune diseases like autoimmune hemolytic anemia (itself more common in diseases such as systemic lupus erythematosus, rheumatoid arthritis, Hodgkin's lymphoma, and chronic lymphocytic leukemia).

- Spur cell hemolytic anemia

- Any of the causes of hypersplenism (increased activity of the spleen), such as portal hypertension.

- Acquired hemolytic anemia is also encountered in burns and as a result of certain infections (e.g. malaria).

- Lead poisoning resulting from the environment causes non-immune hemolytic anemia.

- Runners can suffer hemolytic anemia due to "footstrike hemolysis", owing to the destruction of red blood cells in feet at foot impact.

- Low-grade hemolytic anemia occurs in 70% of prosthetic heart valve recipients, and severe hemolytic anemia occurs in 3%.

Megaloblastic anemia (or megaloblastic anaemia) is an anemia (of macrocytic classification) that results from inhibition of DNA synthesis during red blood cell production. When DNA synthesis is impaired, the cell cycle cannot progress from the G2 growth stage to the mitosis (M) stage. This leads to continuing cell growth without division, which presents as macrocytosis.

Megaloblastic anemia has a rather slow onset, especially when compared to that of other anemias.

The defect in red cell DNA synthesis is most often due to hypovitaminosis, specifically a deficiency of vitamin B and/or folic acid. Vitamin B deficiency alone will not cause the syndrome in the presence of sufficient folate, as the mechanism is loss of B dependent folate recycling, followed by folate-deficiency loss of nucleic acid synthesis (specifically thymine), leading to defects in DNA synthesis. Folic acid supplementation in the absence of vitamin B prevents this type of anemia (although other vitamin B-specific pathologies may be present). Loss of micronutrients may also be a cause. Copper deficiency resulting from an excess of zinc from unusually high oral consumption of zinc-containing denture-fixation creams has been found to be a cause.

Megaloblastic anemia not due to hypovitaminosis may be caused by antimetabolites that poison DNA production directly, such as some chemotherapeutic or antimicrobial agents (for example azathioprine or trimethoprim).

The pathological state of megaloblastosis is characterized by many large immature and dysfunctional red blood cells (megaloblasts) in the bone marrow and also by hypersegmented neutrophils (those exhibiting five or more nuclear lobes ("segments"), with up to four lobes being normal). These hypersegmented neutrophils can be detected in the peripheral blood (using a diagnostic smear of a blood sample).

Anisocytosis is identified by RDW and is classified according to the size of RBC measured by MCV. According to this, it can be divided into

- Anisocytosis with microcytosis – Iron deficiency, sickle cell anemia

- Anisocytosis with macrocytosis – Folate or vitamin B deficiency, autoimmune hemolytic anemia, cytotoxic chemotherapy, chronic liver disease, myelodysplastic syndrome

Increased RDW is seen in iron deficiency anemia and decreased or normal in thalassemia major (Cooley's anemia), thalassemia intermedia

- Anisocytosis with normal RBC size – Early iron, vit B12 or folate deficiency, dimorphic anemia, Sickle cell disease, chronic liver disease, Myelodysplastic syndrome

Mechanical hemolytic anemia is a form of hemolytic anemia due to mechanically induced damage to red blood cells. Red blood cells, while flexible, may in some circumstances succumb to physical shear and compression. This may result in hemoglobinuria. The damage is induced through repetitive mechanical motions such as prolonged marching ("march hemoglobinuria") and marathon running. Mechanical damage can also be induced through the chronic condition microangiopathic hemolytic anemia or due to prosthetic heart valves.

Repetitive impacts to the body may cause mechanical trauma and bursting (hemolysis) of red blood cells. This has been documented to have occurred in the feet during running and hands from Conga or Candombe drumming. Defects in red blood cell membrane proteins have been identified in some of these patients. Free haemoglobin is released from lysed red blood cells and filtered into the urine.

The gold standard for the diagnosis of Vitamin B deficiency is a low blood level of Vitamin B. A low level of blood Vitamin B is a finding that normally can and should be treated by injections, supplementation, or dietary or lifestyle advice, but it is not a diagnosis. Hypovitaminosis B can result from a number of mechanisms, including those listed above. For determination of cause, further patient history, testing, and empirical therapy may be clinically indicated.

A measurement of methylmalonic acid (methylmalonate) can provide an indirect method for partially differentiating Vitamin B and folate deficiencies. The level of methylmalonic acid is not elevated in folic acid deficiency. Direct measurement of blood cobalamin remains the gold standard because the test for elevated methylmalonic acid is not specific enough. Vitamin B is one necessary prosthetic group to the enzyme methylmalonyl-coenzyme A mutase. Vitamin B deficiency is but one among the conditions that can lead to dysfunction of this enzyme and a buildup of its substrate, methylmalonic acid, the elevated level of which can be detected in the urine and blood.

Due to the lack of available radioactive Vitamin B, the Schilling test is now largely a historical artifact. The Schilling test was performed in the past to help determine the nature of the vitamin B deficiency. An advantage of the Schilling test was that it often included Vitamin B with intrinsic factor.

Many patients eventually develop acute myelogenous leukemia (AML). Older patients are extremely likely to develop head and neck, esophageal, gastrointestinal, vulvar and anal cancers. Patients who have had a successful bone marrow transplant and, thus, are cured of the blood problem associated with FA still must have regular examinations to watch for signs of cancer. Many patients do not reach adulthood.

The overarching medical challenge that Fanconi patients face is a failure of their bone marrow to produce blood cells. In addition, Fanconi patients normally are born with a variety of birth defects. A good number of Fanconi patients have kidney problems, trouble with their eyes, developmental retardation and other serious defects, such as microcephaly (small head).

The first line of therapy is androgens and hematopoietic growth factors, but only 50-75% of patients respond. A more permanent cure is hematopoietic stem cell transplantation. If no potential donors exist, a savior sibling can be conceived by preimplantation genetic diagnosis (PGD) to match the recipient's HLA type.

Diamond–Blackfan anemia is characterized by normocytic or macrocytic anemia (low red blood cell counts) with decreased erythroid progenitor cells in the bone marrow. This usually develops during the neonatal period. About 47% of affected individuals also have a variety of congenital abnormalities, including craniofacial malformations, thumb or upper limb abnormalities, cardiac defects, urogenital malformations, and cleft palate. Low birth weight and generalized growth delay are sometimes observed. DBA patients have a modest risk of developing leukemia and other malignancies.

A 2006 Cochrane review did not find evidence sufficient for the use of androgenic anabolic steroids. Corticosteroids are sometimes used; however, this is recommended only when severe liver inflammation is present.

Sylimarin has been investigated as a possible treatment, with ambiguous results. One review claimed benefit for S-adenosyl methionine in disease models.

The effects of anti–tumor necrosis factor medications such as infliximab and etanercept are unclear and possibly harmful. Evidence is unclear for pentoxifylline. Propylthiouracil may result in harm.

Evidence does not support supplemental nutrition in liver disease.

Although in rare cases liver cirrhosis is reversible, the disease process remains mostly irreversible. Liver transplantation remains the only definitive therapy. Today, survival after liver transplantation is similar for people with ALD and non-ALD. The requirements for transplant listing are the same as those for other types of liver disease, except for a 6-month sobriety prerequisite along with psychiatric evaluation and rehabilitation assistance (i.e., Alcoholics Anonymous). Specific requirements vary among the transplant centers. Relapse to alcohol use after transplant listing results in delisting. Re-listing is possible in many institutions, but only after 3–6 months of sobriety. There are limited data on transplant survival in patients transplanted for acute alcoholic hepatitis, but it is believed to be similar to that in nonacute ALD, non-ALD, and alcoholic hepatitis with MDF less than 32.

Most patients with "ETV6-ACSL6"-related disease present with findings similar to eosinophilia, hypereosinophila, or chronic eosinophilic leukemia; at least 4 cases presented with eosinophilia plus findings of the red blood cell neoplasm, polycythemia vera; three cases resembled acute myelogenous leukemia; and one case presented with findings of a combined Myelodysplastic syndrome/myeloproliferative neoplasm. Best treatments for "ETV6-ACSL6"-related disease are unclear. Patients with the polycythemia vera form of the disease have been treated by reducing the circulating red blood cell load by phlebotomy or suppressing red blood cell formation using hydroxyurea. Individual case studies report that "ETV6-ACSL6"-associated disease is insensitive to tyrosine kinase inhibitors. Best treatment currently available, therefore, may involve chemotherapy and bone marrow transplantion.

Ondansetron, a 5HT3 antagonist, appears to have promise as a treatment.

In the United States there are four approved medications for alcoholism: disulfiram, two forms of naltrexone, and acamprosate. Several other drugs are also used and many are under investigation.

- Benzodiazepines, while useful in the management of acute alcohol withdrawal, if used long-term can cause a worse outcome in alcoholism. Alcoholics on chronic benzodiazepines have a lower rate of achieving abstinence from alcohol than those not taking benzodiazepines. This class of drugs is commonly prescribed to alcoholics for insomnia or anxiety management. Initiating prescriptions of benzodiazepines or sedative-hypnotics in individuals in recovery has a high rate of relapse with one author reporting more than a quarter of people relapsed after being prescribed sedative-hypnotics. Those who are long-term users of benzodiazepines should not be withdrawn rapidly, as severe anxiety and panic may develop, which are known risk factors for relapse into alcohol abuse. Taper regimes of 6–12 months have been found to be the most successful, with reduced intensity of withdrawal.

- Acamprosate may stabilise the brain chemistry that is altered due to alcohol dependence via antagonising the actions of glutamate, a neurotransmitter which is hyperactive in the post-withdrawal phase. By reducing excessive NMDA activity which occurs at the onset of alcohol withdrawal, acamprosate can reduce or prevent alcohol withdrawal related neurotoxicity. Acamprosate reduces the risk of relapse amongst alcohol dependent persons.

- Disulfiram (Antabuse) prevents the elimination of acetaldehyde, a chemical the body produces when breaking down ethanol. Acetaldehyde itself is the cause of many hangover symptoms from alcohol use. The overall effect is severe discomfort when alcohol is ingested: an extremely fast-acting and long-lasting uncomfortable hangover. This discourages an alcoholic from drinking in significant amounts while they take the medicine.

- Naltrexone is a competitive antagonist for opioid receptors, effectively blocking the effects of endorphins and opioids. Naltrexone is used to decrease cravings for alcohol and encourage abstinence. Alcohol causes the body to release endorphins, which in turn release dopamine and activate the reward pathways; hence when naltrexone is in the body there is a reduction in the pleasurable effects from consuming alcohol. Evidence supports a reduced risk of relapse among alcohol dependent persons and a decrease in excessive drinking. Nalmefene also appears effective and works by a similar manner.

- Calcium carbimide works in the same way as disulfiram; it has an advantage in that the occasional adverse effects of disulfiram, hepatotoxicity and drowsiness, do not occur with calcium carbimide.

The Sinclair method is a method of using naltrexone or another opioid antagonists to treat alcoholism by having the person take the medication about an hour before they drink alcohol, and only then. The medication blocks the positive reinforcement effects of ethanol and hopefully allows the person to stop drinking or drink less.

Evidence does not support the use of selective serotonin reuptake inhibitors (SSRIs), tricyclic antidepressants (TCAs), antipsychotics, or gabapentin.

Clonal hypereosinophilia, also termed Primary hypereosinophelia or clonal eosinophilia, is a grouping of hematological disorder characterized by the development and growth of a pre-malignant or malignant population of eosinophils, a type of white blood cell, in the bone marrow, blood, and/or other tissues. This population consists of a clone of eosinophils, i.e. a group of genetically identical eosinophils derived from a sufficiently mutated ancestor cell.

The clone of eosinophils bear a mutation in any one of several genes that code for proteins that regulate cell growth. The mutations cause these proteins to be continuously active and thereby to stimulate growth in an uncontrolled and continuous manner. The expanding population of eosinophils, initially formed in the bone marrow may spread to the blood and then enter into and injure various tissues and organs.

Clinically, clonal eosinophilia resembles various types of chronic or acute leukemias, lymphomas, or myeloproliferative hematological malignancies. However, many of the clonal hypereosinophilias are distinguished from these other hematological malignancies by the genetic mutations which underlie their development and, more importantly, by their susceptibility to specific treatment regiments. That is, many types of these disorders are remarkably susceptible to relatively non-toxic drugs.

OSLAM syndrome is a rare autosomal dominant hereditary disorder. Its name is an initialism of "osteosarcoma, limb anomalies, and erythroid macrocytosis with megaloblastic marrow syndrome". OSLAM syndrome was recognised and described by Mulvilhill "" as a syndrome that increases susceptibility to tumours and is characterised by an impaired regulation of bone and marrow development.

Individuals with OSLAM syndrome have an elevated risk of bone cancer, limb abnormalities, and enlarged red blood cells.