Anemia—"low blood"—means that a patient has too few red blood cells or too little in their blood of the iron-containing pigment, hemoglobin. Hemoglobin in red cells picks up oxygen from the air we inhale and carries it to the tissues, where it is released to provide energy and to power the many processes that life requires. As anemia worsens, a patient's energy and ability to function drops, and, if it gets really bad, the patient will die. Depending on how severe it is, patients with anemia will lack strength and stamina, and their mental acuity will decrease.