Why is There Mucus in My Dog's Stool?

Chihuahua sitting in front of teal background.
Mucus in the stool can indicate an internal problem for your dog.

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Most owners have an idea about what their dog's stool normally looks like and anything abnormal-looking may cause them some worry or confusion. While mucus in a dog's stool is a fairly common finding and isn't always concerning, sometimes it can mean there's a problem in need of addressing.

Knowing more about what mucus in your dog's stool may mean can help you keep them healthy and regular.

Why Do Dogs Have Mucus in Their Stool?

Mucus can appear in a dog's stool naturally from the lubrication of the intestines. A small amount of mucus from time to time is completely normal as it allows feces to slide through the colon. If more mucus is seen in the stool on a regular basis, however, it can indicate an issue.

Too much mucus in the stool most often means there is excessive inflammation in your dog's colon and this condition is called colitis.

The colon is the last part of the intestinal tract that stool travels through before it exits a dog's body. When the colon becomes inflamed, colitis occurs and excessive mucus can coat your dog's stool.

The reasons for this inflammation of the colon include various intestinal parasites like whipworms and Giardia, stress, bacterial infections, like E. coli and Salmonella, ingestion of spoiled or contaminated food, inflammatory bowel disease (IBD), allergies, and trauma.

Diagnosing Why a Dog Has Mucus in Their Stool

Diagnostic tests will need to be run in order to determine the cause of the mucus in your dog's stool. Your veterinarian will talk to you about any potential stressors and dietary indiscretion and then start with some basic tests to rule out some common issues.

Microscopic fecal examinations will screen for intestinal parasites and fecal cultures and cytologies will look for bacterial infections. If these tests are negative, and there is no indication of dietary indiscretion, stress, or trauma, more chronic reasons for the inflammation will be explored. Allergies and IBD can be more difficult to diagnose and may involve food elimination diets.

These various diagnostic tests will also ensure that what you are seeing is in fact mucus and not fat. Fat can look similar to mucus since it gives a greasy coating to the stool. But the reasons why a dog has fat in the stool are different than the reasons why it may have mucus. It may mean your dog is simply eating too much fat, or it could mean an issue with the gallbladder, pancreas, or other things.

Treatment of Mucus in Stool

The treatment for excessive mucus in your dog's stool will depend on the underlying reason for it. Parasites and infections may need to be treated with parasiticides and antibiotics. Probiotics and special diets may need to be consumed, and the inflammation in the intestines may need to be addressed with steroids.

Some causes of mucus in the stool, like allergies and IBD, are chronic and will require ongoing management.

How to Prevent Mucus in a Dog's Stool

Since mucus in the stool can sometimes occur due to intestinal parasites, it is important to give your dog regular parasite prevention to decrease the likelihood of this issue occurring. These medications are often found alongside heartworm preventatives and are typically given monthly. Annual fecal examinations to check for parasites are also recommended and are often done when you bring your dog into the vet for its annual physical examination.

Probiotics and prebiotics can help facilitate a normal, healthy intestinal tract and therefore discourage infections and inflammation. Because of this, it may also be helpful to administer a mixture of these products, called a synbiotic, to your dog on a daily basis. These products come in various forms and flavors, and many are designed specifically for dogs. Some even contain other helpful ingredients like beta-glucans, vitamins, and more.

Finally, ensuring your dog doesn't eat contaminated or expired food and isn't living with chronic stress can help prevent mucus from occurring in its stool. These things aren't always easy, but being aware of the potential causes of excessive mucus in the stool can help you prevent it from happening in your dog.