Does your kitty have diarrhea? This common condition could be the cause.
man comforting his cat
Credit: Veera Tsõbo / EyeEm / Getty

No cat parent wants to see their companion suffer from diarrhea, let alone clean up after it. If your cat is having our poor kitty could have colitis, common condition that causes diarrhea in humans, cats, dogs, and other animals. Colitis in cats is sometimes related to a condition called inflammatory bowel disorder, but there are many other possible causes. Fortunately, most cases of colitis can be treated with medications, diet changes, and veterinary supportive care.

What Causes Colitis in Cats?

Colitis is the inflammation of the colon (sometimes called the large bowel). Cats can develop colitis regardless of age, breed, or sex. This condition may happen suddenly (acute colitis) or can be a chronic condition. Chronic colitis often occurs as a result of another medical condition. It is often connected to inflammatory bowel disease, a condition that causes chronic inflammation of the gastrointestinal tract.

Potential causes of colitis in cats include:

  • Inflammatory bowel disease (IBD)
  • Irritable bowel syndrome
  • Stress/anxiety
  • Intestinal parasites
  • Food intolerance or sensitivity
  • Dietary indiscretion (eating something they shouldn't, like human food)
  • Infections of the GI tract (bacterial, fungal, viral)
  • Pancreatitis
  • Trauma to the GI tract
  • Feline Immunodeficiency Virus (FIV)

Signs and Symptoms of Colitis in Cats

When cats have diarrhea, it can involve only the large intestines, just the small intestines, or both. Cats with small bowel diarrhea often experience vomiting, weight loss, and lethargy. Blood in small bowel diarrhea will look dark in color and may resemble coffee grounds or tar. Conversely, blood in the stool from large bowel diarrhea looks like fresh red blood.

It's possible for cats to have both kinds of diarrhea at the same time, especially in those with inflammatory bowel disease. However, colitis alone is less likely to cause nausea, vomiting, and weight loss.

Signs of colitis in cats include:

  • Soft or runny stool that may contain mucus or red blood
  • Defecating outside the litter box
  • Increased frequency of bowel movements
  • Straining to defecate (this may look like constipation)
  • Discomfort while defecating
  • Appetite changes
  • Increased flatulence
  • Discomfort in the lower abdomen (usually caused by cramping or gas)

If your cat is exhibiting any of these signs, contact your veterinarian for advice. You will probably need a vet visit to help your kitty feel better.

How to Treat Colitis in Cats

Treatment for colitis in cats will depend on the underlying cause. Your vet will have a conversation with you about your cat's diarrhea and medical history. After doing a physical exam, the vet will probably recommend some diagnostic tests. This usually starts with a stool sample to look for parasites and infections. The vet may also suggest X-rays of your cat's abdomen to look for anything abnormal, like a foreign body or a mass. Blood tests may also be necessary to assess organ function, electrolyte balance, and blood cells.

If your vet suspects IBD, you might be referred to a specialist for advanced diagnostics like ultrasound, MRI, endoscopy, or exploratory surgery.

Colitis in cats is often treated with a combination of methods. This usually includes medications and diet changes.


If your cat's colitis is caused by parasites, then your vet will prescribe a dewormer to treat the specific type of parasite found.

Antibiotics like tylosin and metronidazole are often used to treat colitis in cats. In addition to treating bacterial infections, metronidazole also has anti-inflammatory properties that can ease the diarrhea itself. Tylosin may promote beneficial gut bacteria while destroying harmful bacteria. 

Cats with IBD are sometimes treated with corticosteroids to reduce inflammation and moderate the immune system (because it plays a role in IBD). Cats on corticosteroids must be carefully monitored to avoid side effects like immune system suppression, diabetes, and organ damage. When corticosteroids don't help, immunosuppressive drugs like chlorambucil or azathioprine may be used.

Diet Changes

Many cases of colitis can be managed through diet changes. Your cat may need a temporary diet change until the diarrhea is resolved. In cases of chronic colitis or IBD, vets often recommend diets with hydrolyzed protein or novel proteins like rabbit or kangaroo. Ask your vet for advice regarding the best diet to feed your cat.

Home Remedies

Some cat parents like to try natural remedies, fiber supplements, or over-the-counter medications to help treat diarrhea caused by colitis. However, these methods may not work and can even make things worse. Never give OTC drugs made for humans, as these may be toxic to cats. Ask your vet for advice before starting any kind of supplement, herb, OTC drug, or other natural remedy for colitis in cats.

Hospital Care

Hospitalization may be necessary for cats with severe colitis in order for them to get supportive care. This may include intravenous fluids to rehydrate and balance electrolytes as well medications to provide comfort and treat the cause of the colitis.

Reduce Stress

Some cases of colitis are brought on by stress, especially in cats with existing IBD. You can take steps to reduce your cat's stress and anxiety at home. This may not stop the diarrhea, but it can prevent future flare-ups. Although a visit to the vet might increase your cat's stress level temporarily, it's often the only way to begin treatment. It's best not to postpone a vet visit—your cat's diarrhea will probably get worse without treatment.

What's the Outlook? The Future for Cats with Colitis

Acute colitis in cats will often resolve with basic treatment. However, cats with chronic colitis or IBD may need more intensive treatments and can experience periodic flare-ups. These cats may need to remain on a special veterinary diet and/or medication for life. Cats with chronic conditions like this will need to see the vet for frequent check-ups.