Hematinics such as iron, vitamin B12, folic acid, and erythropoietin are used to treat various types of anemia. Iron deficiency, vitamin B12 or B9 deficiency, blood loss, and bone marrow disorders can all cause anemia by disrupting the balance of red blood cell production and destruction. Oral iron supplements are usually the first treatment for iron-deficiency anemia, while vitamin B12 and B9 deficiencies may be treated with supplements or injections depending on severity. Erythropoietin injections can help stimulate red blood cell production in conditions like chronic kidney disease or cancer chemotherapy-induced anemia.