Read This Before Giving Your Dog Milk of Magnesia!

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Milk of Magnesia is a very useful laxative/antacid for quick relief of abdominal discomfort, indigestion and especially constipation.

But is this over-the-counter product safe enough for dogs?

Can I Give My Dog Milk of Magnesia?Here’s the deal:

Magnesium hydroxide, the only active ingredient and a naturally-occurring mineral, is not harmful for animals when it is reasonably dosed.

And you’ll be happy to know that Milk of Magnesia is equally effective for dogs. But please keep reading to learn more!

Dogs Can Take Milk of Magnesia

In fact, there is a veterinary version of this antacid/laxative (made for horses and canines) that relieves indigestion, gastric reflux and mild constipation.

OTC Milk of Magnesia is actually one of the safer conventional medicines for dogs. It compares favorably to Maalox because the latter contains too many active ingredients. 


Run It Past Your Vet

Magnesium Hydroxide in a suspension of water (ie. Milk of Magnesia) may not make sense for your dog’s particular situation.

Sometimes recurring bowel problems are indicative of undiagnosed medical conditions. It could be as simple as the dog having impacted stool, but even that requires a vet’s help.

The point is this:

There are many scenarios where giving Milk of Magnesia would be the wrong approach. Just because it may not be dangerous, doesn’t mean providing Magnesium Hydroxide makes sense.

Pro Tip: Using pumpkin to help your dog with constipation will always be preferred to any pharmaceutical.

Dosing Milk of Magnesia

Generally, a safe dose for dogs is 2ml to 5ml given every 4 to 6 hours (when used as an antacid).

And as a laxative, 7ml to 25ml given once a day is sufficient. The liquid suspension solution can be added to your dog’s drinking water.

The above amounts are only for reference. Consult with a vet first!

Both Antacid And Laxative

As an antacid, the magnesium contents of Milk of Magnesia will act as a neutralizer in your dog’s stomach.

A combination of acidic and hydroxide ions produces water to help neutralize acidity in the digestive tract. This reduction of stomach acid works to alleviate mild tummy pain.

By the same token, Milk of Magnesia also works as a laxative by stimulating the intestines (again to release water). This tends to result in normalized and regular bowel movements.

So Milk of Magnesia will not only reduce acid production in your dog’s stomach, but it can also stimulate defecation.

Reasons For Bowel Problems

A sudden diet change can cause your dog to become constipated or diarrhea. That’s why a quick diet change should be avoided. Instead, a gradual transition is highly recommended.

Stress can also make your dog constipated. And just like with humans, stress can result in hyperacidity.

When your dog gets nervous or feels threatened in some way, the stomach may release acid (leading to hyperacidic conditions or even ulcer).

Constipation and/or hyperacidity can be a sign of other serious problems (particularly in the digestive tract area).

Important: Take your dog for a check up if the symptoms are persistent and ongoing.

The Bottom Line

When appropriate and conservatively dosed, Milk of Magnesia can be given to your dog.

It is pretty safe. Still, you should run it past your vet before providing it for any reason.

What Do You Think? Have Your Say Below…

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18 thoughts on “Read This Before Giving Your Dog Milk of Magnesia!”

  1. Maria V Castro says:

    For an older 5 pound Chihuahua, how much can she take of Milk of Magnesia?

  2. Can I give my dog Milk of Magnesia? She has a liver tumor and is trying to go, but has watery stool. A very small amount comes out as she struggles. She goes through this every two or three months.

  3. Milk of Magnesia worked great for my German Shepherd. She was constipated and her feces were too dry due to a change in her diet (she ate too many bones). She had difficulty evacuating her feces during her morning walk. I could see she was struggling. She had only part of her feces out but could not pass them completely.

    Later that day, I gave her 15ml of Milk of Magnesia. I walked her for 30 minutes until she was finally able to push the feces out completely. She was very relieved. The next day (in the morning) she was completely fine. But her feces were too liquid and that is due to the effects of Milk of Magnesia.

  4. Can I use Milk of Magnesia to lower phosphorus levels in my dog who has renal failure, and a tumor on her liver?

  5. My 13 pound Pomeranian is very constipated. I tried 1cc of Milk of Magnesia and it’s not working. The vet does not think there is an obstruction.

    1. 1cc isn’t enough. Like it says above, 7 to 25 ml/cc.

  6. I need an antacid for my dog who has bad reflux at night. She usually has Antepsin but it is sold out everywhere. On here it says that Milk of Magnesia is safe to give but, looking at the ingredients, it lists the artificial sweetener Sodium Saccharin in it. I was told this was toxic to dogs and should never be given. I am confused, is Milk of Magnesia safe for dogs or not?

    1. Look for Original Flavor Milk of Magnesia and you will find that unsweetened, unflavored choices are still out there. I have the Phillips version and there are store brands with identical formulas. It might take some research and possibly mail ordering, but fortunately you should be able to avoid those unwanted ingredients.

  7. Our vet prescribed Milk of Magnesia for our mini Poodle who contracted a bacterial infection. Our main concern is she definitely does not have constipation; quite the contrary, she has been plagued by diarrhea for the last 2 days. We are wondering if Magnesia will also help to stop the diarrhea. She’s also on Flagyl (metronidazole). It’s been a tough couple of days. Thanks!

    1. Lucinda, I agree. I left my little Toy Yorkie with the vet for a couple of days with other dogs and contacted a bacterial infection. My Yorkie has been ill with diarrhea for the last 8 days and has lost weight, has blood in her stool. Also wondering if Magnesia will help stop the diarrhea.

    2. I give my Pomeranian a table spoon of pumpkin and it clears up almost the same day.

  8. Can you make clearer for me the term ‘Liquid suspension solution’

    1. Suspension means that the liquid contains small pieces of the drug. This means it is not completely dissolved, not homogeneous, so it is important to shake it or stir it.

  9. What is the measurement for milk of magnesia in teaspoons or ounces? I have nothing to measure ml.

    1. Hi Susan. As a general rule, 1/2 a teaspoon to 1 teaspoon when using it as an antacid for your dog. For laxative use, it is 1.5 to 5 teaspoons. Please take into account the weight of your dog when using these guidelines. You may want to check with your vet as a precaution before administering it.

  10. Please heed the previous commenter. Having checked a number of websites for the correct dosage to give a dog as a laxative, the amounts you suggest per pound are up to 50 fold higher than they should be! Please correct your numbers.

    1. Thanks for bringing this to my attention! I’ve updated the information accordingly.

  11. The correct dosage is 2.5ml – 5ml as an antacid, 7.5ml – 15ml as a laxative. That’s per dog, not per pound.

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