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Anemia: the signs, getting tested, iron and vitamin B12, and treatment
For anyone told their blood count, hemoglobin or iron is low; anyone tired, weak, pale or dizzy and wondering why; anyone with heavy periods; anyone pregnant; anyone just handed iron pills or B12 shots; and anyone worried about a baby or young child. The National Heart, Lung, and Blood Institute (NHLBI, part of the NIH) says anemia develops when your blood produces a lower-than-normal amount of healthy red blood cells, so your body does not get enough oxygen-rich blood; that the most common type is iron-deficiency anemia; and that mild anemia is common and treatable. This page passes on, by name, what NHLBI says: the signs, the causes (including blood loss and heavy periods), the blood count and the other tests, the foods with iron and vitamin B12, and the treatments. It builds the words to say to a doctor, and prints a card to keep.
Right now
- Chest pain, fainting, trouble breathing, or heavy bleeding that will not stop (including vomiting blood, or black, tarry stools): call 911 (ours). Do not wait for an appointment. Our GI bleeding guide has more on bleeding you cannot see.
- A child swallowed iron pills? Call Poison Help at 1-800-222-1222, free, any hour; if the child is not breathing or will not wake, call 911 (ours). Keep iron pills where children cannot reach them.
- Thoughts of suicide? Call or text 988, any hour (ours).
More help
- Linked to it, on this site: GI bleeding · Period diary · Kidney disease · Celiac disease · Crohn’s disease · Sickle cell disease · Pregnancy and a new baby · When it might be a poisoning.
- Food: Food help.
- Care and costs: When you need a doctor and can’t pay · My medicines list · When medicine costs too much · Get ready for your appointment.
- In a crisis: Help right now (988, 911). All our free tools.
This page and its wording were written with AI (Claude) for Scarlet Beast (our AI policy). No doctor or nurse has reviewed it. The facts were read on October 16, 2026 on eight NHLBI (NIH) pages: What Is Anemia?, Symptoms, Treatment and Management, Anemia in Pregnancy, Iron-Deficiency Anemia and Vitamin B12–Deficiency Anemia (last updated March 24, 2022), and Diagnosis and Causes and Risk Factors (last updated December 18, 2025). Ours: the 911 line; Poison Help for a child who swallowed iron pills, and keeping them out of reach; not starting iron on your own (built on NHLBI’s line that too much iron can damage your organs); 988 for thoughts of suicide; not stopping or changing a medicine on your own; the questions to ask at a visit; health centers, food help and medicine costs when money is tight; and the order of the steps. What we left out: brand names, doses, the daily iron and B12 amount tables, a count of how many people have anemia, the rarer types (hemolytic and aplastic anemia) in detail, research studies, and clinical pages for providers. This page saves nothing and loads no trackers.