Brand Name(s):

  • Milk of Magnesia®
  • Milk of Magnesia-Concentrated®
  • Phillips Milk of Magnesia®

WHY is this medicine prescribed?

Magnesium hydroxide is used on a short-term basis to treat constipation.

This medication is sometimes prescribed for other uses; ask your doctor or pharmacist for more information.

HOW should this medicine be used?

Magnesium hydroxide come as a tablet and liquid to take by mouth. It usually is taken as needed for constipation. Follow the directions on the package or on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take magnesium hydroxide exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.

Shake the liquid well before each use.

What SPECIAL PRECAUTIONS should I follow?

Before taking magnesium hydroxide,

  • tell your doctor and pharmacist if you are allergic to magnesium hydroxide or any other drugs.
  • tell your doctor and pharmacist what prescription and nonprescription medications you are taking, including vitamins.
  • tell your doctor if you have or have ever had kidney disease.
  • tell your doctor if you are pregnant, plan to become pregnant, or are breast-feeding. If you become pregnant while taking magnesium hydroxide, call your doctor.

What should I do IF I FORGET to take a dose?

This medication usually is taken as needed. If your doctor has told you to take magnesium hydroxide regularly, take the missed dose as soon as you remember it. However, if it is almost time for the next dose, skip the missed dose and continue your regular dosing schedule. Do not take a double dose to make up for a missed one.

What SIDE EFFECTS can this medicine cause?

Magnesium hydroxide may cause side effects. If you experience any of the following symptoms, call your doctor immediately:

  • stomach cramps
  • upset stomach
  • vomiting
  • diarrhea

If you experience a serious side effect, you or your doctor may send a report to the Food and Drug Administration's (FDA) MedWatch Adverse Event Reporting program online [at Web Site] or by phone [1-800-332-1088].

What should I know about STORAGE and DISPOSAL of this medication?

Keep this medication in the container it came in, tightly closed, and out of reach of children. Store it at room temperature and away from excess heat and moisture (not in the bathroom). Throw away any medication that is outdated or no longer needed. Talk to your pharmacist about the proper disposal of your medication.

What OTHER INFORMATION should I know?

Ask your pharmacist any questions you have about taking this medicine.

It is important for you to keep a written list of all of the prescription and nonprescription (over-the-counter) medicines you are taking, as well as any products such as vitamins, minerals, or other dietary supplements. You should bring this list with you each time you visit a doctor or if you are admitted to a hospital. It is also important information to carry with you in case of emergencies.

AHFS® Consumer Medication Information. © Copyright, The American Society of Health-System Pharmacists, Inc., 7272 Wisconsin Avenue, Bethesda, Maryland. All Rights Reserved. Duplication for commercial use must be authorized by ASHP.

Last Reviewed: September 1, 2010.