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MagGel Side Effects

Generic Name: magnesium oxide

Medically reviewed by Last updated on Nov 1, 2020.

Note: This document contains side effect information about magnesium oxide. Some of the dosage forms listed on this page may not apply to the brand name MagGel.

For the Consumer

Applies to magnesium oxide: oral capsule, oral tablet

What are some side effects that I need to call my doctor about right away?

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.
  • Severe diarrhea.

What are some other side effects of this drug?

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:

  • Diarrhea.

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

For Healthcare Professionals

Applies to magnesium oxide: compounding powder, oral capsule, oral tablet


Magnesium toxicity symptoms may include: hypotension, nausea, vomiting, facial flushing, urine retention, ileus, depression, lethargy, muscle weakness, respiratory depression, arrhythmia, cardiac arrest, coma, and death.[Ref]

Frequency not reported: Hypermagnesemia, magnesium toxicity[Ref]


Frequency not reported: Diarrhea, nausea, abdominal cramping[Ref]


1. National Institutes of Health (NIH) "Magnesium: fact sheet for health professionals. Available from: URL:" ([2016, Feb 11]):

2. Guerrera MP, Volpe SL, Mao JJ "Therapeutic uses of magnesium." Am Fam Physician 80 (2009): 157-62

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

Some side effects may not be reported. You may report them to the FDA.