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Milk of magnesia: Things to know

Constipation is treated with milk of magnesia, which is a common and efficient remedy. It is available without a prescription from drug shops.

This page discusses what milk of magnesia is, how to use it, which conditions it can cure, and the most prevalent negative effects.

What is milk of magnesia?

Magnesium hydroxide, often known as milk of magnesia, can be used as an antacid or a saline laxative.

This kind of laxative aids stool loosening by pulling moisture into the colon.

A person can buy milk of magnesia over the counter (OTC) without a prescription, but if they have repeated spells of constipation, they should consult their doctor.

Unless their doctor advises it, parents and guardians should avoid providing milk of magnesia to children under the age of six.

Uses and effects

Magnesia milk is used for a variety of purposes, including:

The original version of milk of magnesia aids in bowel movement production in 30 minutes to 6 hours.

Milk of magnesia may aid with illnesses including sunburn and acne, in addition to constipation and acid reduction, while scientific data is limited.

Magnesium milk for sunburn

Some people claim that putting a thin coating of milk of magnesia topically to a sunburn can assist to relieve the discomfort and burning.

Though this may help for some people, there are no studies or empirical data to back up its usage in the treatment of sunburn.

A person seeking sunburn treatment should consult their physician. Other over-the-counter medicines, such as aloe vera, may be more effective.

Magnesium milk for acne

Some people feel that magnesia milk might aid with acne treatment. The belief is based on the drug’s capability to help break up surface oils.

The sole study on its usage for acne was published in 1975. According to the study, using milk of magnesia in combination with orally ingesting 250 mg of tetracycline and bathing two times daily with a nonfat soap helped clean up acne pustules and reduce inflammation.

There have been no more research on the use of using milk of magnesia topically or eating it orally to cure acne. Alternative acne treatment options should be discussed with a doctor.


Milk of magnesia can be purchased as a pill or a liquid. When taking a pill, it is common to chew the tablet before swallowing it.

Milk of magnesia is available in two strengths: ordinary and concentrated. Children under the age of 12 should not be given the concentrated liquid.

Different people of milk of magnesia may be purchased at pharmacy shops or online.


People should not take any more medication than their doctor or the package instructions suggest.

Though dosages vary, a person should not take more than the suggested dose in a 24-hour period.

A person can drink liquid magnesia milk by mixing it with milk or water. Before measuring a dosage, give the bottle a good shake. The dose is determined by the reason for the medication’s use as well as the patient’s age.

The dosages for milk of magnesia based on use and age are described in the sections below.

Milk of magnesia for constipation

When taking milk of magnesia, people of legal drinking age should drink a full glass (8 ounces) of water with each dose. To ensure accuracy, use the 15-milliliter (ml) dosage cup or spoon supplied. It’s better to take the prescription before going to bed.

The dose in milliliters changes based on a person’s age when using the original type of milk of magnesia for constipation:

  • Adults can take 30–60 ml.
  • Children ages 6–11 can take 15–30 ml.
  • Ask a doctor before giving this medication to children under 6 years old.

The dose for the concentrated form of milk of magnesia is lower:

  • Adults can take 15–30 ml.
  • Ask a doctor before giving this medication to children under 12 years old.

Chewable pills are also available for children. Each dosage should be accompanied with a full glass of liquid. Depending on your age, you’ll need to take a different dose:

  • Children ages 6–12 can take 3–6 tablets per day.
  • Children ages 2–6 can take 1–3 tablets per day.
  • Ask a doctor before giving this medication to children under 2 years old.

Milk of magnesia should not be used as a laxative for more than 7 days in a row. Anyone who is still in need of a laxative or is experiencing prolonged stomach pain should consult a physician.

Constipation is generally relieved within 6 hours of drinking milk of magnesia. If a person does not have a bowel movement after taking milk of magnesia, they should discontinue use and consult a physician.

In some circumstances, constipation may be caused by an underlying condition that needs more medical attention.

Milk of magnesia for other digestive issues

People can take various types of milk of magnesia to treat heartburn and acid indigestion in addition to constipation alleviation.

Adults should drink 5–15 ml of water at a time and repeat up to four times per day as needed. They should not drink more than 60 milliliters of water in a 24-hour period.

When used as an antacid, milk of magnesia may also have a laxative effect. Milk of magnesia should not be used as an antacid for more than 14 days in a row.

Before using milk of magnesia to address other digestive difficulties in children under the age of 12, see a doctor.

Adverse effects

The majority of people who consume milk of magnesia have no negative side effects.

The following are the most prevalent milk of magnesia adverse effects:

  • vomiting
  • skin flushing
  • drowsiness
  • diarrhea
  • stomach cramps
  • nausea

More significant adverse effects are also possible with magnesia milk. Stop taking the drug and seek medical help if you encounter any of the following people:

  • severe nausea or vomiting
  • lightheadedness
  • rectal bleeding
  • slow heartbeat
  • no bowel movement after taking it

If a person consumes more milk of magnesia than suggested or for a longer period of time, serious side effects are more likely to develop.


To avoid getting dehydrated, people who are taking this medicine should drink lots of water. If someone gets diarrhea after taking milk of magnesia, they should not take it again.

If someone takes too much milk of magnesia, they should seek medical help right away. An overdose can cause the following symptoms:

  • mood change
  • little or no urination
  • severe diarrhea
  • slow or irregular heartbeat
  • muscle weakness

Some people are allergic to magnesia milk. The following are symptoms of an allergic response that require medical attention:

  • swelling of the face, lips, tongue, or throat
  • difficulty breathing
  • hives

Milk of magnesia should be avoided by people who have renal problems. The medicine should also be avoided by the following people:

  • people who experience sudden bowel changes that last longer than 14 days
  • people with symptoms such as nausea, diarrhea, or stomach pain
  • people on a magnesium-restricted diet

Pregnancy and nursing

Magnesium may be able to get through the placenta and into the fetus’s body. However, due to a lack of evidence, experts are unsure if milk of magnesia is safe to use during pregnancy.

Small levels of magnesium may also find their way into breast milk, but experts are unsure of its safety.

As a result, it is generally recommended to avoid taking milk of magnesia when pregnant or breastfeeding, or to see a doctor before doing so.


Milk of magnesia interacts with a wide range of drugs, affecting their effectiveness. Prescription and over-the-counter drugs, as well as vitamins and supplements, are among them.

Milk of magnesia can prevent tablets from being effectively absorbed because of how it affects the fluid in the gut.

As a result, if you routinely use other drugs, such as OTC medications, vitamins, or prescription prescriptions, you should see your doctor before using milk of magnesia.


Milk of magnesia is a well-known and efficient laxative for treating constipation in the short term.

For constipation, people should not take milk of magnesia for more than 7 days at a time, and for other digestive difficulties, they should not use it for more than 14 days at a time.

Continuous symptoms may indicate a more significant gut health concern, so if the problem persists, a person should see a doctor.

Milk of magnesia acts by pulling water from the surrounding tissue into the intestine. This means it can prevent the body from absorbing a variety of other medications, such as prescription medications, supplements, and vitamins.

Before consuming milk of magnesia, anyone taking medicine for a health condition should see a doctor.



Obianuju Chukwu

She has a degree in pharmacy and has worked in the field as a pharmacist in a hospital. Teaching, blogging, and producing scientific articles are some of her interests. She enjoys writing on various topics relating to health and medicine, including health and beauty-related natural treatments, the nutritional worth of various foods, and mental wellness.