Folic acid deficiency anemia, also called folate deficiency anemia, type of anemia resulting from a deficient intake of the vitamin folic acid (folate). Folic acid, a B vitamin, is needed for the formation of heme, the pigmented, iron-containing portion of the hemoglobin in red blood cells (erythrocytes). A deficient intake of folic acid impairs the maturation of young red blood cells, which results in anemia. The disease also is characterized by leukopenia (a deficiency of white blood cells, or leukocytes), by thrombocytopenia (a deficiency of platelets), by ineffective blood formation in the bone marrow, and by progressive gastrointestinal symptoms, such as sore tongue, fissures at the corners of the mouth, diarrhea, inflammation of the pharynx or esophagus, and ulceration of the stomach and intestine.

Folic acid deficiency develops over a period of several months and may result from a diet that is low or lacking in foods containing folic acid. The deficiency may also be brought on by poor absorption of folic acid in the intestine due to celiac disease or anticonvulsant drug therapy or by faulty metabolism of the vitamin in the liver due to cirrhosis. It can also occur in pregnant women and in persons with severe hemolytic anemia (dissolution of red blood cells by hemolysin). The oral administration of folic acid produces quick improvement in all symptoms; an adequate diet results in cure in cases due to simple malnutrition.