Anemia is a decrease in the amount of oxygen-carrying substance
(hemoglobin) found in red blood cells. Anemia causes weakness, pale skin, and
general tiredness (fatigue).
Anemia can be caused by blood loss or bleeding, an increase in the
destruction of red blood cells, or a decrease in the production of red blood
cells. Types of anemia include iron deficiency anemia, folic acid deficiency
anemia, and vitamin B12 deficiency anemia, among others. Each type of anemia is
treated differently.