Hesperian Health Guides

Vitamins and Mineral Supplements

Iron, ferrous sulfate, ferrous gluconate

Ferrous sulfate is useful in the treatment or prevention of most cases of anemia. Treatment with ferrous sulfate by mouth usually takes at least 3 months.
     Iron works better when taken with vitamin C (either by eating fruits and vegetables, or taking a vitamin C tablet).

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Iron sometimes upsets the stomach and is best taken with meals. Also, it can cause constipation especially in older people, and it may make the stools (feces) look black. See advice for constipation.
     Drinking liquid iron supplements blackens the teeth. Drink it through a straw or brush the teeth after.


Be sure the dose is right. Too much ferrous sulfate is poisonous. Do not give iron to severely malnourished persons. Wait until they have recovered their health.

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Different forms of iron contain different concentrations of this mineral. For example, a 300 mg tablet of ferrous sulfate contains about 60 mg of iron. But a 325 mg tablet of ferrous gluconate contains 36 mg of iron. So read the label of your tablets, syrup, or other iron supplement to learn the iron content.

To PREVENT anemia in pregnant and breastfeeding women
Give 300 mg ferrous sulfate (60 mg iron) each day. Iron should also be taken daily by women who plan to become pregnant. A combined iron and folic acid supplement is even better, because folic acid helps prevent birth defects.

To TREAT someone who is already anemic
Give this amount once a day, or divide into 2 doses if it upsets the stomach:
Under 2 years 125 mg
ferrous sulfate
Use iron syrup, or crush
about ¼ of a 300 mg
ferrous sulfate tablet in
breast milk
Give enough to provide
25 mg iron
2 to 12 years old 300 mg
ferrous sulfate
1 tablet of 300 mg
ferrous sulfate
Give enough to provide
60 mg iron
Over 12 years 600 mg
ferrous sulfate
2 tablets of 300 mg
ferrous sulfate
Give enough to provide
120 mg iron

Folic acid, folate

Folic acid is an important vitamin that aids a baby’s healthy development in the first weeks of pregnancy.

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A combined folic acid and iron supplement may be more convenient than taking the two separately. Whether combined with iron or used alone, the dose is the same.
     It is best to start taking folic acid before you become pregnant so your body has enough to meet the baby’s needs in the early weeks. Continue taking it throughout the first 3 months of pregnancy.

     Give 400 to 500 mcg each day.

This page was updated:02 Jan 2018