My Dog Has Mucus in Their Stool, What's Wrong?

For someone without a dog, this might seem like an odd topic, but for those of us with a dog, it matters, since we always worry about our dog's health and obviously find it strange when we see stool with mucus.

A dog's stool generally isn't very mucousy — it should look somewhat lubricated but not excessively so, and definitely not covered in anything resembling white or green mucus. If our dog's stool looks like this, something's going on.

Why does my dog have mucus in their stool?

We should make it clear that it's completely normal for a dog's stool to look somewhat "shiny," since the intestine itself lubricates the colon to help with bowel movements. On top of that, there are the substances secreted by our dog's anal glands during defecation. So what would actually be unusual is for our dog's stool to look dry instead of somewhat lubricated.

Excess lubrication in the stool can give the impression of mucus — something gel-like and whitish or greenish in appearance. It's like a layer of mucus coating the stool, to be explicit.

Stool is the end result of a dog's digestion, giving us valuable information about how the digestive system and the body overall are functioning. Normal stool has a firm, solid consistency, which you can pick up off the ground without any trouble.

With that clarified, the main reasons behind mucus in a dog's stool are:

• Excessive growth of intestinal bacteria.
• Colitis / poisoning / diet changes / intolerances.
• Parasites and/or polyps.
• Foreign objects.

Intestinal bacteria imbalance causes mucus

We all have good bacteria in our intestines that help digest food or break it down into digestible matter. There are bacteria beneficial to the digestive system and harmful bacteria.

And, despite what we might think, there needs to be a natural balance between them. When an imbalance occurs, whether from excessive growth of harmful bacteria or of beneficial bacteria, excess mucus is produced.

Among the main functions of this community of intestinal bacteria (the microbiome) are protecting the intestine against other pathogens entering, forming a protective barrier against toxins, allergens, and carcinogens, and playing a role in producing vitamins such as B12.

Many factors can negatively affect what's known as the gut flora, or intestinal microbiota. This includes systemic illness, sudden diet changes, low-quality kibble with high percentages of indigestible protein, fermented foods, not to mention factors like stress itself, all triggering changes in the appearance of stool and in digestion itself.

Mucus in stool from diet

If a food doesn't agree with our dog, it will trigger a reaction in their intestine that can lead to mucus appearing in the stool, precisely because of an imbalance in the intestinal microbiota.

During the holidays, we tend to indiscriminately offer our four-legged friends various foods, without realizing that these excesses often translate into imbalances in the gut flora.

Some dog breeds, like Collies, suffer more from diet changes. Also, the more purebred a dog is, the more vulnerable they tend to be to these sudden diet changes.

A food intolerance or allergy, just like any product that may have poisoned our dog, can cause fecal mucus and diarrhea, along with possible skin rashes.

Diet is a key factor, so it could simply be something our dog ate that didn't agree with them, or something much more serious, like an undiagnosed intolerance.

Minimizing the impact on stomach health comes down to simple steps such as reducing sudden kibble changes — to do this, you should pick a brand that's easy to find and fits your budget.

If you're going to leave your dog at a daycare, it's a good idea to bring their kibble along, and lastly, if for genuinely valid reasons you decide to change your pet's diet, it should be done gradually — that is, you'll gradually mix the old food with the new one, so the gut flora is disrupted as little as possible.

Intestinal parasites cause mucus in stool

We never tire of recommending deworming our dog internally as often as our vet recommends. Some dogs live in high-risk areas and need deworming more often than others.

Yes, intestinal parasites, also known as intestinal worms, can cause mucus in stool, among many other things. If we notice yellow stool with mucus, or dark stool that also has mucus and small white specks like little grains of rice in the stool... those are parasites.

But careful — not every parasite is visible in the stool. Our dog could have parasites we can't detect, except through a vet check-up.

Generally, we see phlegm or mucus in the stool without seeing the parasite itself, since the infestation isn't very heavy and only the parasite's eggs are present in the stool — these aren't visible except in a clinical lab using special sedimentation and flotation techniques, so my recommendation again is: see your specialist. Polyps can also cause mucus and blood in the stool.

Foreign objects that irritate the digestive system

We already know how dogs are — they'll eat their kibble just as easily as a bit of stick, a piece of plastic, or even a ball. If we look away for a moment, whether out of hunger or while playing, they're capable of swallowing anything.

Some foreign objects can be sharp or pointed and cause intestinal irritation — to give you an idea, similar to what happens to skin when we cut ourselves, the same thing happens in the intestine with foreign objects: the lining starts defending itself against this aggressor through secretions — mucous, serous, purulent, bloody — depending on how severe the damage is.

What should I do if my dog has mucus in their stool?

If you notice mucus in your dog's stool, it's important to take them to a vet, since mucus in stool is sometimes caused by simple things, but many other times by serious health problems.

Without knowing the cause of the excess mucus, it's impossible to set up the right treatment. That's why we should go to a vet clinic and let a specialist in canine health advise us.

If, besides mucus, our dog also shows blood in the stool, diarrhea, fever, or any other symptom that catches our attention, then we should make the vet visit a priority.