Ferrous Fumarate Side Effects

Medically reviewed by Drugs.com. Last updated on Apr 11, 2024.

Applies to ferrous fumarate: oral capsule, oral tablet, oral tablet extended release.

Serious side effects of ferrous fumarate

WARNING/CAUTION: Even though it may be rare, some people may have very bad and sometimes deadly side effects when taking a drug. Tell your doctor or get medical help right away if you have any of the following signs or symptoms that may be related to a very bad side effect:

• Signs of an allergic reaction, like rash; hives; itching; red, swollen, blistered, or peeling skin with or without fever; wheezing; tightness in the chest or throat; trouble breathing, swallowing, or talking; unusual hoarseness; or swelling of the mouth, face, lips, tongue, or throat.
• Black, tarry, or bloody stools.
• Fever.
• Very upset stomach or throwing up.
• Very bad belly pain.
• Throwing up blood or throw up that looks like coffee grounds.

Other side effects of ferrous fumarate

All drugs may cause side effects. However, many people have no side effects or only have minor side effects. Call your doctor or get medical help if any of these side effects or any other side effects bother you or do not go away:

• Belly pain.
• Diarrhea.
• Constipation.
• Change in color of stool to green.
• Not hungry.
• Upset stomach or throwing up.
• Stomach cramps.

These are not all of the side effects that may occur. If you have questions about side effects, call your doctor. Call your doctor for medical advice about side effects.

You may report side effects to the FDA at 1-800-332-1088. You may also report side effects at https://www.fda.gov/medwatch.

See also:

For healthcare professionals

Applies to ferrous fumarate: compounding powder, oral liquid, oral suspension, oral tablet, oral tablet chewable, oral tablet extended release.

Gastrointestinal adverse events

• Frequency not reported: Nausea, vomiting, gastrointestinal discomfort, constipation, diarrhea, discolored (blackened) stools, tooth discoloration, anorexia, epigastric pain, fecal impaction^[Ref]

Hematologic

• Frequency not reported: Hemosiderosis^[Ref]

Hypersensitivity

• Frequency not reported: Allergic reaction^[Ref]

Further information

Ferrous fumarate side effects can vary depending on the individual. Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Note: Medication side effects may be underreported. If you are experiencing side effects that are not listed, submit a report to the FDA by following this guide.

Medical Disclaimer