Fact Checked

What is Milk of Magnesia?

Y. Chen
Y. Chen

Milk of magnesia, also known by the generic name magnesium hydroxide, is a medicine that is used as a hydrating laxative and an antacid. It is not a dairy product, but rather a milky-white liquid that is made from magnesium hydroxide, purified water, and sodium hypochlorite. This medicine usually relieves uncomfortable gastrointestinal symptoms within 30 minutes and constipation within six hours.

Treatment of Stomach Discomfort

A cup of milk of magnesia.
A cup of milk of magnesia.

Magnesium hydroxide is an alkaline suspension, which means that it is able to neutralize acids. When a patient swallows this medicine, the hydroxide ions in it react with the hydrogen ions in stomach acid, transforming both into water. This makes milk of magnesia effective in fighting excess stomach acid, which can cause indigestion, heartburn, and stomach ulcers. When used as an antacid, the usual adult dose is from 0.02 – 0.05 oz (500 mg to 1,500 mg).

Treatment of Constipation

Milk of magnesia may be useful in treating dandruff.
Milk of magnesia may be useful in treating dandruff.

The magnesium in milk of magnesia is what makes it an effective laxative. The mineral ions draw water into the intestinal tract from the surrounding body tissues. This extra water softens and increases the volume of feces, which stimulates the nerves in the intestines and causes a bowel movement. For the treatment of constipation, an adult dose is between 0.07 – 0.18 oz (2,000 mg and 5,000 mg).

Other Uses

Milk of Magnesia can be harmful to fetuses.
Milk of Magnesia can be harmful to fetuses.

Many people use this product in a number of off-label ways, including as a topical treatment for dandruff, seborrheic dermatitis, acne, and other skin conditions. It reportedly can help reduce body odor as well. There are few if any scientific studies that support these claims, but using milk of magnesia on the skin is unlikely to cause any serious side effects in most people.


Many people use milk of magnesia to treat acne.
Many people use milk of magnesia to treat acne.

Milk of magnesia can react with certain antibiotics, and may be harmful to fetuses or newborns. Patients who are taking antibiotics, or who are pregnant or nursing, need to consult with a medical professional before taking this type of medicine. As with any other medication, milk of magnesia does occasionally produce side effects, including weakness, nausea, vomiting, and diarrhea. Most patients tolerate it well, so those with severe side effects should be sure to contact a healthcare provider. All patients should only use magnesium hydroxide for up to one week, unless otherwise instructed by a medical professional.

Milk of magnesia has been used to treat stomach discomfort.
Milk of magnesia has been used to treat stomach discomfort.

Patients with severe or chronic kidney disease are typically advised to limit their intake of magnesium, so they should only use milk of magnesia under the orders of a healthcare provider who is familiar with the condition. Healthy kidneys remove this mineral from the body quickly while unhealthy kidneys may not be able to effectively do so. This could lead to toxic levels in the blood, a condition called hypermagnesemia.


Milk of magnesia is often flavored with mint.
Milk of magnesia is often flavored with mint.

The first documented medical use of magnesium as a treatment for stomach problems was by Sir James Murray, who created a liquid suspension of this mineral in 1829. The original formula for magnesium hydroxide was developed in 1880 by a man named Charles Henry Phillips. It was sold under the brand Phillips' Milk of Magnesia.


Milk of magnesia is sold over the counter. It comes in the traditional liquid suspension, as well as chewable tablets and capsules, and may be unflavored or flavored, usually in mint or cherry. Health professionals often recommend taking it with a full glass of juice or water to help with absorption.

You might also Like

Discussion Comments


MOM mixed with table sugar and applied to bed sores results in healing. It really works!


I have been taking Milk of Magnesia for years because of an anal fissure. The fissure has now been repaired through surgery so I no longer need it. What long term damage would have been caused to me?


It works.


I have used milk of magnesia for a sunburn remedy. Just put it on a cotton ball and apply to red areas. I cannot speak for how it works; I only know that it does. It takes the fire and burning feeling out. This was told to me by a older lady who was raised in africa by her missionary parents. They had limited resources there, which led her mother to try this. I thought she was crazy when she suggested this, but it works!

I have two boys who are so sun sensitive that they often are pink despite the sunscreen use. It dries to a white chalkiness on your skin, and can be reapplied if needed. I do not know how it works, or how young of a child it is safe to use on. I applied it to my school age kids. I know it sounds crazy but try it.


I am 11 weeks pregnant and I have been having bouts of constipation on and off the last couple of weeks. I read the reviews of MOM and along with the doctor's advice, I decided to buy a bottle of the cherry flavor. I took it last night and had a BM within three hours and it felt so good after not going to the bathroom in eight days. I would definitely recommend this product because it really does work.


Another site lists Milk of Magnesia as part of a home remedy for canker sores. 1/2 hydrogen peroxide mixed with 1/2 water dabbed on the sore, then apply milk of magnesia for a soothing effect.


Also try M.O.M. as an alternative, non-aluminum deodorant (and also seems to work as antiperspirant in some). Do a search on milk of magnesia and deodorant, if interested. I am a recent convert in my attempt to avoid questionable ingredients after my breast cancer diagnosis.

I have tried it on acne, but like everything else, it did not help with that. I did use it as a mask occasionally, but the absorptive effects on my Exxon Valdez oil-spill of a face were short-lived.


My family doc recommended MOM (Milk of Magnesia) for my two year old daughter as she has been on and off again constipated, to the point that her BM's were like small stones and very, very dry.

She has been on it for two weeks and outside of being very runny in the beginning she has been consistently pasty the last two days or so.

MOM has to work through your system for the first week or so before your body stops reacting with pure water. My daughter would basically have "wet farts" and no it's not quite that bad. this has really helped us in this department.


Milk of magnesia is also a great way to cure acne related issues and works as good as if not better than expensive facial treatments. Apply the milk of magnesia on the face and let dry for 15 to 30 minutes. Then wash off with a warm wet wash cloth.


anon13846 didn't say "Wikipedia calls it pseudoscience quackery." They said, "Wikipedia has references..."

In fact, their article on Homeopathy has 167 inline citations (footnotes) which reference a plethora of medical journals (with PubMed links), the AMA, FDA, NHS, plus a few 'third string' sources like Newsweek and BBC.

Read Wikipedia's policy pages about Verifiability and Reliable Sources. "Articles should rely on reliable, third-party, published sources with a reputation for fact-checking and accuracy. This means that we only publish the opinions of reliable authors, and not the opinions of Wikipedians."

And anyone considering using homeopathic products -- especially on babies -- please read some of those many scientific references linked from their Homeopathy article. The FDA article under Links if nothing else....

PS A Wikipedia article said Milk of Magnesia might help seborrheic dermatitis (anyone?) so I Googled for more data, and came across this page. So, I'm not adverse to all alt-medicine, I just research it well first, which I do before I take anything "FDA approved" too, either OTC or prescribed.


anon13846: I hardly think Wikipedia is the "Master-Of-All-Truth"! Anyone can post as many "facts" on Wikipedia as they want to. (For Instance) A said group of people want to change the definition on Wikipedia to say that Elephants only have two knees per leg, or that cow's only have one stomach. And if you get enough people backing that theory, the admin will actually change the definition to the newly perceived. Please be cautious when using Wikipedia for any medical info. Use WebMD or call a local hospital, family physician, etc. when seeking medical advice.

I have used the homeopathic teething tablets on my kids while they were teething, not because that's what I believe in, but it really helped when other traditional methods did not. It is a Natural Remedy so-to-speak thing, but hardly dangerous unless uncle joe-bob-henry-bob is making it in his basement. Most of the Over-the-counter homeopathic remedies are A-OK!


Homeopathy is considered implausible and dangerous by the mainstream (evidence-based) medical community. Some homeopathic remedies contain mercury. Wikipedia has references that call it pseudoscience quackery, or, in the words of a 1998 medical review, "placebo therapy at best and quackery at worst." Please consider it as a last resort, if at all.


I saw on the newspaper that it heals acne too! Just put it on your face...

That's what I am trying..


can milk of magnesia be used (and i know its awfully mean) as a prank without bad side effects? the person has normal bodily functions and fits the criteria to be OK to take it if he was constipated so the only difference between him and a constipated person is he isn't constipated but would he be OK to take it?


I have an 8 month old who was born at 32 weeks. she had a tight sphincter and was put on MOM daily by her GI doctor. It was done to prevent having to use dilators and it did work, I just didn't like the thought of her being on this daily also if she didn't have a bowel movement every 3rd to fourth day or was really distended. I was instructed to give mild soapy water enemas about 5ccs. She is now on Miralax and it is working wonderfully. What is your thought on this treatment because I noticed you suggested homeopathic instead. I am asking because my mother-in-law thinks I was depleting her of potassium and electrolytes. Even though she couldn't poop and had no diarrhea to speak of.


Babies on breast milk only can often go days at a time, or even up to a week with no BM. This is not defined as constipation. This is actually normal, and speaks to the fact that breast milk is such a perfect food and so completely assimilated, that there is very little waste. Parents often mistake this for constipation. Constipation is defined as a hard stool.

If your baby is truly "constipated," I suggest a Homeopathic Remedy to put his/her body in balance. Homeopathy is a natural form of medicine that seeks to eliminate symptoms based on the principal of "like cures like" stimulating the body to help itself. Unlike some herbs, Homeopathic remedies are safe while pregnant or breastfeeding, and are safe for babies and children.

Tina Williams-Wolf, IBCLC, RLC, HMA

Classic Homeopath


I'm 16 years old and i have had constipation for 3 days. I tried enemas, laxatives, everything will this stuff help me. I have been drinking coke since i was 7.


Babies are *supposed* to drink breast milk and it won't make them constipated. More likely, it's something else that is making your baby constipated because she shouldn't need to drink water or juice or anything else - at that age, they can still just live on breast milk. Take her to the doctor!


i have a 7 month old baby girl who get severely constipated, someone has told me to try milk of magnesium daily. what is your advice on this. she get so constipated because she refuses to take any other liquid except for breast milk. it is very hard to get her to drink anything, water, juices or formula milk.


Can you tell me who was the UK firm who would have been manufacturing Milk of Magnesia in 1920-30. I am tracing family history and my mother worked for this firm whoever they were.

Post your comments
Forgot password?
    • A cup of milk of magnesia.
      By: Elena Schweitzer
      A cup of milk of magnesia.
    • Milk of magnesia may be useful in treating dandruff.
      By: Jasmin Merdan
      Milk of magnesia may be useful in treating dandruff.
    • Milk of Magnesia can be harmful to fetuses.
      By: Oleksandr Bondar
      Milk of Magnesia can be harmful to fetuses.
    • Many people use milk of magnesia to treat acne.
      By: Ocskay Bence
      Many people use milk of magnesia to treat acne.
    • Milk of magnesia has been used to treat stomach discomfort.
      By: Claudia Nagel
      Milk of magnesia has been used to treat stomach discomfort.
    • Milk of magnesia is often flavored with mint.
      By: margo555
      Milk of magnesia is often flavored with mint.
    • Milk of magnesia is used as a hydrating laxative and antacid.
      By: Africa Studio
      Milk of magnesia is used as a hydrating laxative and antacid.