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Magnesium Sulfate Granules (Epsom Salt)

Generic name: Magnesium Sulfate Granules (Epsom Salt) [ mag-NEE-zhum-SUL-fate ]
Drug classes: Laxatives, Minerals and electrolytes, Miscellaneous anticonvulsants

Medically reviewed by Last updated on May 21, 2023.

Uses of Magnesium Sulfate Granules:

Granules used by mouth:

Granules used as soaks:

  • It is used to treat minor sprains or bruises.

For all uses of this medicine (magnesium sulfate granules):

  • It may be given to you for other reasons. Talk with the doctor.

What do I need to tell my doctor BEFORE I take Magnesium Sulfate Granules?

For all uses of this medicine (magnesium sulfate granules):

  • If you are allergic to this medicine (magnesium sulfate granules); any part of this medicine (magnesium sulfate granules); or any other drugs, foods, or substances. Tell your doctor about the allergy and what signs you had.

Granules used by mouth:

  • If you have any of these health problems: Bowel block, belly pain, upset stomach, rectal bleeding, throwing up, or change in bowel habits lasting longer than 2 weeks.

This is not a list of all drugs or health problems that interact with this medicine (magnesium sulfate granules).

Tell your doctor and pharmacist about all of your drugs (prescription or OTC, natural products, vitamins) and health problems. You must check to make sure that it is safe for you to take this medicine (magnesium sulfate granules) with all of your drugs and health problems. Do not start, stop, or change the dose of any drug without checking with your doctor.

What are some things I need to know or do while I take Magnesium Sulfate Granules?

For all uses of this medicine (magnesium sulfate granules):

  • Tell all of your health care providers that you take this medicine (magnesium sulfate granules). This includes your doctors, nurses, pharmacists, and dentists.
  • If you are on a low-magnesium diet, talk with your doctor.
  • Tell your doctor if you are pregnant, plan on getting pregnant, or are breast-feeding. You will need to talk about the benefits and risks to you and the baby.

Granules used by mouth:

  • Try to space other drugs from this one by 2 hours. This medicine stops many drugs from getting into the body.
  • Do not use this medicine (magnesium sulfate granules) for more than 1 week unless told to do so by your doctor.
  • If you have rectal bleeding or you do not have a bowel movement after using this medicine (magnesium sulfate granules), talk with your doctor.
  • Talk with the doctor before you give this medicine (magnesium sulfate granules) to a child younger than 6 years old.

How is this medicine (Magnesium Sulfate Granules) best taken?

Use this medicine (magnesium sulfate granules) as ordered by your doctor. Read all information given to you. Follow all instructions closely.

Granules used by mouth:

  • Read package labeling carefully.
  • Mix in 8 ounces (240 mL) of water.
  • Lemon juice may be added to make it taste better.
  • Take with a full glass of water.

Granules used as soaks:

  • Mix with water as you have been told before using this medicine (magnesium sulfate granules).
  • Soak for as long as you were told by your doctor, then pat dry.

What do I do if I miss a dose?

  • This medicine is used on an as needed basis. Do not use more often than told by the doctor.

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:

For all uses of this medicine (magnesium sulfate granules):

  • 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.

Granules used by mouth:

  • Very upset stomach or throwing up.
  • Black, tarry, or bloody stools.
  • Cramps.

What are some other side effects of Magnesium Sulfate Granules?

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:

Granules used by mouth:

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

If OVERDOSE is suspected:

If you think there has been an overdose, call your poison control center or get medical care right away. Be ready to tell or show what was taken, how much, and when it happened.

How do I store and/or throw out Magnesium Sulfate Granules?

  • Store at room temperature in a dry place. Do not store in a bathroom.
  • Keep all drugs in a safe place. Keep all drugs out of the reach of children and pets.
  • Throw away unused or expired drugs. Do not flush down a toilet or pour down a drain unless you are told to do so. Check with your pharmacist if you have questions about the best way to throw out drugs. There may be drug take-back programs in your area.

Consumer Information Use and Disclaimer

  • If your symptoms or health problems do not get better or if they become worse, call your doctor.
  • Do not share your drugs with others and do not take anyone else's drugs.
  • Some drugs may have another patient information leaflet. Check with your pharmacist. If you have any questions about this medicine (magnesium sulfate granules), please talk with your doctor, nurse, pharmacist, or other health care provider.
  • If you think there has been an overdose, call your poison control center or get medical care right away. Be ready to tell or show what was taken, how much, and when it happened.

Further information

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