Iron supplement
Ferrous Sulfate (Iron)
Tablet or syrup
Quick Summary
Iron is needed to make haemoglobin.
Iron deficiency anaemia
Pregnancy
Medical Uses
Iron deficiency anaemia: Treatment.
Pregnancy: Prevention, as advised.
How it's taken
Take on an empty stomach or with food if it upsets your stomach. Vitamin C helps; tea and coffee reduce absorption.
Your doctor decides the right dose for you and how long to take it.
Your doctor decides the right dose for you. Follow their instructions and the label.
Common Side Effects
Constipation
Common.
Dark stools
Harmless.
Nausea
Common.
Interactions
Antacids, calcium, tea
Reduce absorption.
Some antibiotics and thyroid medicine
Take apart.
Critical Warnings
Keep away from children
Black Box Warning: Iron overdose is dangerous for children.
Find the cause
Especially in men and older women.
Sources and further reading
Last updated 21 October 2026. For more detail, see these trusted health organisations.