Colitis in Dogs

Shelby Loos, DVM
By Shelby Loos, DVM on Oct. 21, 2021

In This Article


What Is Colitis in Dogs?

Colitis is a general term that refers to inflammation of a dog’s colon, also known as the large intestine.

The colon is the last part of the gastrointestinal system, following the small intestine.

By the time food gets to a dog’s colon, most of the nutrients have been absorbed, but a large, natural bacterial population within the colon further digests any leftover undigested food.

The colon also absorbs water, so when it’s inflamed and its cells aren’t functioning well, water isn’t absorbed properly, and it is expelled as diarrhea. 

Types of Colitis in Dogs

There are two forms of colitis in dogs:

Acute colitis refers to a sudden onset of symptoms that typically lasts only a few days. We see this often in dogs, and it usually clears up on its own.

Chronic colitis lasts for longer—from weeks to months. With chronic colitis, your dog will have multiple episodes of symptoms that keep coming and going, or symptoms that simply keep going. Either way, chronic colitis in dogs often requires a medical workup.

Symptoms of Colitis in Dogs

Signs of colitis in dogs include:

  • Urgency in needing to go to the bathroom

  • Soft or liquid stool

  • Straining or pain with defecation

  • More frequent bowel movements of smaller volume

  • Stool containing blood or mucus

Dog colitis symptoms will also vary depending on whether your dog has chronic or acute colitis.

Chronic Colitis

Dogs with chronic colitis are typically healthy and seem fine but have soft stools that might contain blood or mucus.

Acute Colitis

Dogs with acute colitis often have a sudden onset of diarrhea that ranges from soft stool to straight liquid. Their stool might also have some bright-red blood and/or mucus.

If your dog has acute colitis, they may have to urgently go outside multiple times and will sometimes go to the bathroom inside the house, despite being house-trained. They might appear to be straining to defecate as well. Vomiting can also occur, but it is not common.

Causes of Colitis in Dogs

In addition to presenting differently, acute and chronic colitis often have different causes.

Causes of Acute Colitis

  • Stress (e.g., boarding, traveling, moving, or environmental changes)

  • Dietary indiscretions (e.g., too many treats, eating people food, or getting into the garbage)

  • Sudden changes in diet

  • Parasites

  • Foreign materials

  • Infectious agents, such as bacteria

Causes of Chronic Colitis

  • Parasites (e.g., giardia or whipworms)

  • Food hypersensitivity

  • Infectious agents, such as bacteria (e.g., campylobacter, salmonella, or clostridium) or a fungal infection like histoplasmosis

  • Foreign materials

  • Cancer

  • Inflammatory bowel disease

  • Dysbiosis (leaky gut)

  • Idiopathic (when your vet is unable to define a specific cause)

Dog Breeds That Are Prone to Colitis

Any dog can get colitis. However, young Boxers and French Bulldogs are more prone to a rare type of colitis called granulomatous colitis.

In granulomatous colitis, a bowel segment becomes thickened or partially blocked due to a bacterial invasion of the intestinal wall. It results in bloody diarrhea and weight loss. Treatment includes antibiotic therapy and dietary changes as well as corticosteroids.

These are the steps a vet will take to diagnose colitis in dogs.

1. Medical History

Vets will start by getting a thorough history (asking you questions about the issue). This information helps your veterinarian to determine if the diarrhea is from the small intestine or from the large intestine.

Questions your vet might ask include:

  • How long ago did this start?

  • What does your dog’s stool look like? Is there blood or mucus in it?

  • Is your dog able to hold it to go outside, or do they have to go urgently?

  • Is your dog straining to defecate?

  • Is there any vomiting, fatigue, or lack of appetite?

  • Has your dog eaten anything recently that they typically don’t eat, or have they gone through a stressful event? Have you changed your dog’s diet?

2. Physical Exam

Next, your vet will perform a thorough physical exam on your dog, including rectal evaluation. They will assess your dog’s dehydration level, check for pain or abnormalities in the abdomen and rectum, and assess the quality of their stool.

3. Fecal Analysis

In cases of both acute and chronic colitis, your vet will do a fecal analysis to determine if there are parasites. If you are taking your dog to the veterinarian for diarrhea, make sure to bring a fresh fecal sample in a sealed bag.

Your veterinarian might diagnose acute colitis just based on the medical history, physical exam, and fecal analysis. However, the exact cause is often unknown since acute colitis usually clears up quickly on its own.

If the diarrhea persists for longer than two weeks, it is classified as chronic diarrhea and requires further medical attention. Typically, this consists of a course of antibiotics followed by a diet trial.

4. Diet Trial

Before pursuing advanced diagnostics, your vet will usually recommend a diet trial for your dog. The recommended prescription diets are low in fat, high in fiber, and formulated either for a sensitive gastrointestinal tract or with a novel protein to determine if there are any food allergies.

5. Abdominal X-Rays or Abdominal Ultrasound

If the diarrhea does not respond to a special diet, the next step is an abdominal ultrasound. This examines your dog’s intestines for any signs of foreign material, thickening of the intestinal wall, or enlarged lymph nodes. The ultrasound surveys the abdomen for any clue as to what might be causing the diarrhea.

6. Colonoscopy

The last step in colitis diagnosis is a colonoscopy. For a colonoscopy, your dog is put under general anesthesia, and a camera is inserted into their rectum and moved along the colon. Your veterinarian will look for any masses, signs of inflammation, or abnormalities. They will then take biopsies of the colonic wall to submit for further analysis.

Treatment for Colitis in Dogs

Do not give any medications at home. Dogs do not metabolize medications the same as humans, so giving your dog a human medication is very dangerous. It can also be counterproductive without knowing the exact cause of the colitis.

Take your dog to the veterinarian if you see any symptoms of colitis. They might initially provide some fluids under your dog’s skin to help with hydration. Then, depending on their findings, they may prescribe one or more of the following treatment options.

Metronidazole, Tylosin, and Sulfasalazine

Metronidazole, tylosin, and sulfasalazine are antibiotics that might also have some anti-inflammatory properties. Courses of these are often tried in the beginning to help resolve colitis, and if it does not improve, then your dog will undergo a diet trial and further diagnostics.

Dietary Fiber

Supplementing the diet with fiber improves diarrhea in many animals. It reduces water in their feces, prolongs transit time (allowing more water to absorb), increases the fecal bulk, and improves the intestine’s ability to contract. You can add fiber through a prescription fiber diet, canned pumpkin, or psyllium.

Bland Diet

A bland diet consists of a simple protein, like boiled chicken (no skin, no spices), cooked hamburger, or fully cooked eggs, as well as a simple carbohydrate, like white or brown rice or white or sweet potatoes. You can even add a small amount of plain, canned 100% pumpkin for fiber (make sure there are no other ingredients).

Prebiotics and Probiotics

Prebiotics act as food for the beneficial bacteria in the colon. They help maintain a healthy bacterial population in the colon, which, in turn, helps resolve diarrhea in dogs.

Probiotics are a protected culture of live bacteria that can help colonize the gastrointestinal system and promote beneficial bacterial balance. This also helps relieve diarrhea.

Prescription Diet

Your dog may be prescribed a novel-protein diet or a hydrolyzed-protein diet in the case of food allergies. Otherwise, high-fiber diets might help in certain cases of colitis.


Your vet may prescribe glucocorticoids for their anti-inflammatory and immune-modulating properties when previous therapy has failed to alleviate your dog’s chronic colitis.

They are used mostly with inflammatory bowel disease, which is diagnosed with a biopsy sample during a colonoscopy. If your dog requires a glucocorticoid to manage their diarrhea, they often have to stay on it long-term.

Recovery and Management of Colitis in Dogs

In cases of acute colitis, full recovery typically happens within a few days. Chronic colitis usually takes a longer time, requiring further diagnostics and trials of different medications and diets to see what helps.

Depending on the underlying cause, chronic colitis in dogs might not be curable, but it can often be managed and controlled through one or more of the following: diet, fiber supplements, antibiotics, and corticosteroids/anti-inflammatories/immune modulators.

Colitis in Dogs FAQs

Does colitis in dogs go away?

Acute colitis often clears up on its own within 24-48 hours. However, it does sometimes require veterinary assistance to fully resolve. Chronic colitis has many potential causes. Some can be treated, curing the colitis, but others can only be managed with medication or diet.

Because many other conditions can have the same symptoms, and because it may be chronic colitis, you should go to the vet if you see:

  • Urgency in needing to go to the bathroom

  • Soft or liquid stool

  • Straining or pain with defecation

  • More frequent bowel movements of smaller volume

  • Stool containing blood or mucus

What triggers colitis in dogs?

Stressful events, such as boarding, traveling, or moving, can trigger an episode of colitis. Eating something that upsets the gastrointestinal tract is another cause. There are many possible triggers, so seek veterinary evaluation if the diarrhea continues beyond 24 hours.

How do you treat colitis in dogs naturally?

As long as the dog still has energy and is eating, you can try a bland diet at home. Consider adding in some pumpkin for fiber as well as probiotics to help with the gut flora.

How much does it cost to treat colitis in dogs?

It depends on the cause and severity. The costs would include the examination, fecal analysis, sometimes blood work to assess hydration, fluids (if given), and medications. In severe cases, where the dog needs to stay at the hospital or requires advanced diagnostics, such as an ultrasound or a colonoscopy, the cost is quite a bit higher.

Can stress cause colitis in dogs?

Yes. Stress is thought to be a common cause of colitis in dogs.

What medication is used for colitis in dogs?

Special diets, fiber supplements, probiotics, antibiotics, and steroids can all be used for colitis depending on the severity, duration of symptoms, and underlying cause.

Shelby Loos, DVM


Shelby Loos, DVM


Dr. Shelby Loos is a 2017 graduate from the University of Florida with a certificate in aquatic animal medicine. After completing a year...

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