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Learning About Iron Supplements


People take iron supplements when their bodies do not have enough iron. Your body uses iron to make hemoglobin.

Hemoglobin is part of red blood cells. It carries oxygen through the body. Without enough oxygen, you may feel weak, dizzy, and short of breath. You may tire easily. You also may feel grumpy, have headaches, and have trouble concentrating.

Most people begin to feel normal after a few weeks of taking iron pills. But you need to take the pills for several months to build up the iron supply in your body. This can take up to 6 months.


  • Ferrous fumarate (Ferrets, Hemocyte, Ircon)
  • Ferrous gluconate (Ferate, Fergon)
  • Ferrous sulfate (Feosol, Fer-Gen-Sol, Fer-in-Sol)

You can buy iron supplements without a prescription. Your doctor will give you directions on how much to take and for how long. Your doctor will also tell you whether you need any testing for iron levels.

Possible side effects

Common side effects may include:

  • Stomach ache.
  • Nausea.
  • Constipation.
  • Black stools.

You may have other side effects or reactions not listed here. Check the information that comes with your medicine.

What to know about taking this medicine

  • Take your medicines exactly as prescribed. Call your doctor or nurse advice line if you think you are having a problem with your medicine.
    • Try to take the pills on an empty stomach about 1 hour before or 2 hours after meals. But you may need to take the iron with food to avoid a stomach ache.
    • Do not take antacids or drink milk or caffeine drinks (such as coffee, tea, or cola) at the same time or within 2 hours of the time that you take your iron pills. They can keep your body from absorbing the iron well.
    • Vitamin C helps your body absorb iron. You may want to take iron pills with a glass of orange juice or some other food high in vitamin C.
    • Iron pills may cause stomach problems, such as heartburn, nausea, diarrhea, constipation, and cramps. Be sure to drink plenty of fluids and eat fruits, vegetables, and fibre each day.
    • Iron pills can change the colour of your stool to a greenish or grayish black. This is normal. But internal bleeding also can cause dark stool. So be sure to tell your doctor about any colour changes.
    • Call your doctor or nurse advice line if you think you are having a problem with your iron pills. Even after you start feeling better, it will take several months for your body to build up its supply of iron.
    • If you miss taking a pill on time, do not take a double dose of iron. Take your next dose at the scheduled time.
  • Liquid forms of iron can stain your teeth. You can mix a dose of liquid iron in water, fruit juice, or tomato juice. Drink it with a straw so that it does not get on your teeth.
  • Check with your doctor or pharmacist before you use any other medicines, including over-the-counter medicines. Make sure your doctor knows all of the medicines and natural health products you take. Taking some medicines together can cause problems.
  • Keep iron tablets out of the reach of small children. Too much iron can be very dangerous.

Follow-up care is a key part of your treatment and safety. Be sure to make and go to all appointments, and call your doctor or nurse advice line (811 in most provinces and territories) if you are having problems. It's also a good idea to know your test results and keep a list of the medicines you take.

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