* Vitamin B12 deficiency: * Achlorhydria-induced malabsorption * Deficient intake * Deficient intrinsic factor, a molecule produced by cells in the stomach that is required for B12 absorption (pernicious anemia or gastrectomy) * Coeliac disease * Biological competition for vitamin B12 by diverticulosis, fistula, intestinal anastomosis, or infection by the marine parasite Diphyllobothrium latum (fish tapeworm) * Selective vitamin B12 malabsorption (congenital—juvenile<unk>  1—and drug-induced) * Chronic pancreatitis * Ileal resection and bypass * Nitrous oxide anesthesia (usually requires repeated instances). * Folate deficiency: * Alcoholism * Deficient intake * Increased needs: pregnancy, infant, rapid cellular proliferation, and cirrhosis * Malabsorption (congenital and drug-induced) * Intestinal and jejunal resection * (indirect) Deficient thiamine and factors (e.g., enzymes) responsible for abnormal folate metabolism. * Combined Deficiency: vitamin B12 & folate. * Inherited Pyrimidine Synthesis Disorders: Orotic aciduria * Inherited DNA Synthesis Disorders * Toxins and Drugs: *Folic acid antagonists (methotrexate) * Purine synthesis antagonists (6-mercaptopurine, azathioprine) * Pyrimidine antagonists (cytarabine) * Phenytoin * Nitrous Oxide * Erythroleukemia * Inborn genetic mutations of the Methionine synthase gene * Di Guglielmo's syndrome * Congenital dyserythropoietic anemia * 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
Normocytic anemia
Normochromic anemia
Pythiosis
Osteomalacia
Agranulocytosis
Hypochromic anemia
Lathyrism