Dealing with doggie diarrhea? This common health condition may be the culprit.
woman hugging her bulldog
Credit: Carol Yepes

If your dog is having diarrhea, it might be a case of colitis. This common condition occurs in humans, dogs, cats, and other animals and usually causes diarrhea, gas, and discomfort. While colitis can have many causes, stress is the biggest culprit. The good news is that colitis is easily detected and can often be managed through diet and medication.

What Causes Colitis in Dogs?

The term colitis simply means inflammation of the colon, also known as the large bowel. Since colitis typically causes diarrhea, it is sometimes referred to as large bowel diarrhea.

Any dog can develop colitis regardless of age, breed, or sex. This condition can happen suddenly (acute colitis) or it may be a chronic condition. Chronic colitis often occurs as a result of another medical condition.

Stress colitis is the most common type of acute colitis in dogs. This happens when stress and anxiety interfere with immune function, leading to inflammation of the large bowel. It's not unusual for dogs to develop acute colitis after a stressful event like boarding, moving, or loud noises like thunderstorms or fireworks.

Other causes of colitis include:

Symptoms of Colitis in Dogs

In general, diarrhea may be related to the large intestines or the small intestines and will present in different ways. Dogs with small bowel diarrhea are more likely to experience vomiting, weight loss, and lethargy. If blood is present in small bowel diarrhea, then it will appear dark like coffee grounds or tar (not fresh red blood as with large bowel diarrhea).

Of course, diarrhea may be related to both the large and small intestines, but in cases of colitis, it is primarily the large bowel that is affected. Signs of colitis in dogs include:

  • Soft or runny stool (often contains mucus or red blood)
  • Increased frequency of bowel movements
  • Straining to defecate (may look like constipation)
  • Discomfort during bowel movements
  • Changes in appetite
  • Increased flatulence
  • Discomfort in the lower abdomen (usually caused by large bowel cramping or gas)

Contact your veterinarian if your dog is exhibiting any of these signs. They can advise you on next steps to get your pup feeling better.

How to Treat Colitis in Dogs

The first step to treating dog colitis is to determine what caused it. Your veterinarian will discuss your dog's health history with you and then perform a physical examination. Next, the vet will run fecal tests to check for parasites and infections in the stool. Abdominal X-rays may be needed to look for GI foreign bodies and tumors. Blood testing may also be recommended to assess electrolyte balance, blood cell counts, and organ function.

Reduce Stress

If the colitis was brought on by stress, then it's important to do what you can to reduce your dog's stress and anxiety at home. This won't necessarily stop the diarrhea, but it can prevent it from getting worse or recurring. Of course, a trip to the vet might temporarily increase your dog's stress level, but it's usually necessary to begin treatment.


Dewormers are used to treat parasitic infections causing colitis in dogs. The exact type of dewormer will depend on the type of parasite.

Metronidazole is a medication used to treat many cases of large bowel diarrhea. This antibiotic can treat bacterial infections, but it also has anti-inflammatory properties that can ease the diarrhea itself. Metronidazole may also be used along with dewormers to treat parasites like Giardia.

Diet Changes

Many cases of colitis can be managed with diet changes alongside medication. Vets typically recommend a  period of fasting for one to two days in order to rest the GI tract. After that, a special diet may be warranted. Your vet will help you find the right diet for your dog.

Natural Remedies

Many dog parents may try feeding their dog pumpkin to help ease their diarrhea caused by colitis, however, this home remedy doesn't always help in all cases. In general, natural supplements or home remedies can be helpful, but these can also make diarrhea worse. Be sure to talk to your vet before starting any kind of supplement, herb, or other natural remedies for colitis.

Hospital Care

Dogs with severe colitis often need to be hospitalized for supportive care. These pups may need intravenous fluids to rehydrate and balance electrolytes. During hospitalization, dogs are sometimes treated with anti-diarrhea drugs to provide relief.

What's the Outlook? Future Care for Dogs with Colitis

Most cases of acute colitis clear up quickly with basic treatment. However, dogs with chronic colitis—especially those with inflammatory bowel disease—may experience flare-ups throughout their lives. These dogs may need to remain on a special vet-recommended diet at all times. Medications are often used to help with flare-ups. Dogs with chronic conditions like this may need to see the vet for frequent check-ups.

When diet and medications are not helping, it may be time for advanced diagnostic testing. Your vet may recommend a colonoscopy and/or MRI to check for more serious issues. This may include a referral to a veterinary internal medicine specialist.