Metamucil for Dogs: Can I Safely Give It to My Dog?

Vets may recommend Metamucil® for dogs with diarrhea or constipation because it is excellent at modifying stool consistency. To give you the facts on this fiber supplement, integrative veterinarian Dr. Julie Buzby explains how Metamucil works, which forms of Metamucil dogs should—and should not—take, and Metamucil’s side effects and safety considerations.

When you think about fiber supplements for humans, Metamucil is probably one of the first products that come to mind. Chances are good that you have noticed the classic orange tubs at the drugstore or watched TV advertisements touting the benefits of Metamucil. Maybe you even have some in your own medicine cabinet.

But what you may not know is that this common over-the-counter dietary fiber supplement for humans can make a useful fiber supplement for dogs, too. That said, don’t stop reading this article to reach for the orange container in your cupboard quite yet.

First, it is important to check with your vet before giving your dog any new medication or supplement. Second, it’s important to know that there are some Metamucil formulations (e.g. wafers, gummies, and flavored powders) that contain inactive ingredients that are harmful to dogs. We’ll dive into this after answering some common questions about Metamucil for dogs.

What is Metamucil?

The active ingredient in Metamucil is psyllium, a derivative of the plant known as Plantago ovata. Psyllium is a viscous soluble fiber that is slowly fermentable. This means it dissolves in water to form a gel (i.e. is soluble and viscous) and sticks around in the GI tract rather than being rapidly broken down by gut bacteria. It also produces less gas than rapidly fermentable types of fiber.

Additionally, Metamucil contains certain amounts of insoluble fibers (i.e. those that don’t dissolve in water). This makes it a “balanced” fiber supplement with many useful properties. As such, it is a good first choice for fiber supplementation for dogs.

(If you want to learn more nitty-gritty details about the types of fiber and what they do, check out my comprehensive article on fiber for dogs.)

What is Metamucil used for in dogs?

In certain situations, your veterinarian may recommend giving your dog Metamucil. Since it is a supplement that was originally made for humans, this is considered “off-label” usage. However, it is ok to give your dog certain formulations of Metamucil under a vet’s supervision for treating constipation, diarrhea, or other issues.

Metamucil for dogs with constipation

Metamucil is great for constipated senior dogs and dogs diagnosed with constipation secondary to disorders that cause dehydration (e.g., kidney failure in dogs). Your vet may also recommend trying it if your dog has gone too long without pooping.

The psyllium in Metamucil can be helpful when a dog is constipated because psyllium swells when it absorbs water. You can think about this sort of like adding water to a dry sponge. When the stool (or the sponge) soaks up water, it becomes softer. This makes it easier for a constipated dog to have a bowel movement.

Additionally, the insoluble fiber portion of Metamucil has a bulk-forming laxative effect. In other words, it creates bulkier stools. Plus, it is mildly irritating to the lining of the intestines, which causes a shorter transit time through the digestive tract.

Due to the combination of these two fiber types, administering Metamucil leads to softer, bulkier stools that move through the gut faster. This can help resolve and prevent constipation.

Metamucil for dogs with diarrhea

If your dog has colitis, inflammatory bowel disease (IBD in dogs), or diarrhea, he or she might also benefit from a fiber supplement like Metamucil. Since the psyllium in Metamucil is good at absorbing water, it can also soak up extra water in the stool (kind of like a sponge). This can lead to more well-formed stools.

For example, one study published in the Journal of Veterinary Internal Medicine looked at using Metamucil and the gastrointestinal diet Hills Prescription Diet i/d to treat dogs with chronic diarrhea. Most dogs showed a good to excellent response (i.e. improved fecal consistency). The researchers indicated that 23 of the 37 dogs in the study had been unsuccessfully treated with Hill’s i/d in the past, which makes it likely that adding the Metamucil is what made the difference.

How much Metamucil should you give a dog?

In the above study, the average amount of Metamucil each dog received was two tablespoons. However, the actual dosage ranged from half a tablespoon to three tablespoons, depending on the dog’s size. Since each dog’s situation is a bit different, the best way to find out how much Metamucil to give your dog is by contacting your vet. He or she can give you a starting dose and then work with you to make modifications to that dose as needed.

What kind of Metamucil can I give my dog?

Your vet can also recommend the best type of Metamucil for your dog. This is a good thing because it can be easy to suffer from “analysis paralysis” when looking at the shelf of Metamucil powders, capsules, wafers, and gummies. Here are some general guidelines for you to discuss with your vet.

Stick with unflavored powder or capsules

The safest forms of Metamucil for dogs are unflavored powder and capsules. Not only are these forms the most fiber-dense varieties available, but they also do not contain any harmful ingredients. (Even then, it’s always best to check the label for xylitol or other harmful ingredients.)

Beware of flavored varieties, gummies, and wafers

Metamucil also comes in flavored powders, gummies, and wafers. These flavored options tend to be more unpalatable to dogs and may contain sugars like sucrose and brown sugar, which can cause gastrointestinal upset in dogs. And the sugar-free version of Metamucil (commonly orange-flavored) contains aspartame which can also cause stomach upset.

However, the most dangerous form is the Metamucil gummies, which contain xylitol (i.e. birch sugar) as an artificial sweetener. Avoid gummies, or any other xylitol-containing products, at all costs because xylitol is extremely toxic to dogs.

How do you give Metamucil to your dog?

If you decide to go with unflavored powder, you can sprinkle it on your dog’s regular food. It is easiest to sprinkle onto wet food, but you can also add it to dry food. Sometimes you need to add some water to get the powder to stick to the food. Keep in mind, though, that adding too much water can turn the powder into a mushy, unpalatable gel-like substance. 

If your furry friend won’t eat the Metamucil powder or you have a larger dog who needs a lot of powder, the capsule version might end up working out better. You can hide it in a favorite treat or right in your dog’s canned food. Or, in many cases, it is safe to use low-sodium chicken broth or a small slice of banana to entice your pup to take Metamucil. 

What are some alternatives to Metamucil?

If you are still struggling to get your dog to take the Metamucil, you can also try some of the tips in my article, Your Dog Won’t Take Pills? Or you may want to reach out to your vet to discuss alternatives to Metamucil.

Metamucil does tend to have more fiber per serving than many other products, but there are other ways to provide fiber for your dog. These include:

• High-fiber prescription dog food
• Veterinary-specific fiber supplements
• Other human fiber supplements like Benefiber (which has less fiber per serving than Metamucil)
• High-fiber foods like canned pumpkin for dogs (Keep in mind that your dog will need to consume a larger amount of pumpkin to supply a similar amount of fiber as a teaspoon or two of Metamucil.)

Your veterinarian can help you figure out the best product and dose for your dog.

Can my dog take Metamucil with other medications?

While talking with your vet about fiber supplements like Metamucil, it is also helpful to mention any medications or supplements your dog is taking. Metamucil can affect the way the body absorbs other medications such as:

• Pain medications (e.g. NSAIDs and gabapentin for dogs)
• Heart medications (e.g., amlodipine)
• Antacids (e.g., omeprazole for dogs)
• Omega-3 fatty acids for dogs

Your vet may recommend giving the medications two hours before or two hours after the Metamucil. This can help prevent issues with poor absorption.

Is Metamucil safe for dogs?

Additionally, like most other medications, it is best to follow your vet’s dosing recommendations. Metamucil is overall safe for dogs (assuming you use a safe version as outlined above). But large amounts can cause diarrhea, constipation, and flatulence. It is also possible for growing puppies to become ill from excess fiber supplementation because it may diminish the absorption of nutrients from their diet.

Also, in rare cases, giving Metamucil without adequate water intake has led to esophageal or intestinal obstructions. Therefore, it is a good idea to try to encourage your dog to drink plenty of water while taking Metamucil. This can help it work effectively and move through the digestive system.

Is Metamucil right for your dog?

Overall, Metamucil is a useful fiber supplement for dogs. It does a great job of helping prevent and treat constipation in dogs and resolve diarrhea. Plus, the side effects of Metamucil are minimal.

However, keep in mind that some formulations (e.g. wafers, gummies, and flavored powders) contain harmful inactive ingredients. Always check the label for xylitol or other problem ingredients before giving Metamucil, or any other product, to your dog.

Also, remember to talk with your veterinarian before deciding to give your dog Metamucil. He or she can help determine if it is the right treatment. Plus, your vet can advise you about the best Metamucil dosage for your dog and recommend additional diagnostics or treatments as needed.

Has your dog taken Metamucil?

Please comment below.