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What Is Inflammatory Bowel Disease In Cats?

Est. read time: 7 min.

Okay, who out there just cleaned up a pile of cat vomit this week? In today’s blog post, we’ll review inflammatory bowel disease in cats, which is one of the top reasons for chronic vomiting (and often, diarrhea) in cats. IBD in cats is similar to irritable bowel syndrome (IBS) or Crohn’s disease in humans.

Is your cat vomiting more than 2-3x/month?

As a cat parent and veterinarian, I’m pretty tolerant of vomit. Cats do it. But is it normal?


Okay, once in a while is normal. But if you find your cat vomiting chronically more than 2-3X/month, something more serious may be going on… and it warrants a trip to the veterinarian. That’s because certain underlying medical problems can cause chronic vomiting in cats, such as:

  • Inflammatory bowel disease (IBD)
  • Metabolic problems (e.g., kidney/renal disease, liver, etc.)
  • Hairballs
  • Parasites
  • Gastrointestinal cancer (like lymphoma)
  • Pancreas problems
  • Food allergy or intolerance
  • Bacterial infections (e.g., Salmonella, Clostridium, Campylobacter)
  • Foreign body (something stuck in the stomach or intestines)
  • Hyperthyroidism (an overactive thyroid gland)
  • A diabetic crisis (e.g., diabetic ketoacidosis)
  • Infectious disease (e.g., fungal infections like histoplasmosis)

What exactly is IBD in cats?

Inflammatory bowel disease in cats is a disorder where inflammatory cells (e.g., white blood cells) attack and infiltrate the lining of the gastrointestinal tract (GIT). This inflammation makes it difficult for normal digestion and absorption of food to occur. It can affect all areas of the entire GIT, from the stomach to the small intestine to the lower colon. I often describe it as an immune system attack on the GIT (e.g., a hypersensitivity or overactive stimulation) and sometimes is caused by an “allergy.” Underlying causes or thoughts of IBD are allergies to:

  • Meat proteins
  • Food additives/preservatives/artificial coloring
  • Milk proteins
  • Gluten (rare, so no, you don’t necessarily need to feed a grain-free diet!)

What types of cats get IBD?

Typically, IBD is seen more in middle-aged to older cats, with Siamese and other purebred cats being slightly more at risk for developing IBD.

What are the signs of IBD in cats?

Signs of irritable bowel disease in cats mostly include chronic gastrointestinal (GI) symptoms such as:

  • Inappetance (not eating) to even increased appetite
  • Lethargy
  • Vomiting 
  • Diarrhea (ranging from pudding-soft stool to watery diarrhea with mucus or even blood)
  • Noisy gut sounds (grumbling or contractions of the intestines)
  • Abdominal pain
  • Abnormal-colored feces (e.g., black, tarry, bloody)
  • Straining to defecate
  • More frequent visits to the litter box
  • Smaller volume of feces in the litter box
  • Greater urgency to use the litter box
  • Flatulence
  • Weight loss
  • Poor haircoat

What’s the diagnosis of IBD in cats?

So, what is your veterinarian going to do to work up your cat for possible inflammatory bowel disease? 

  • A thorough history (e.g., diet, exposure to other cats, medications, etc.)
  • Physical examination (which may reveal thickened loops of intestine, enlarged abdominal lymph nodes, a palpable goiter in the neck, etc.)
  • Basic blood work (like a complete blood count, biochemistry panel, and urine test)* 
  • Thyroid test (T4)
  • A trypsin-like immunoreactivity test (which tests the function of the pancreas)*
  • A cobalamin and folate test (testing for bacterial overgrowth)*
  • Urinalysis
  • A fecal test for parasites, protozoa, and bacteria (e.g., Giardia, Campylobacter, Salmonella, etc.)
  • Radiographs (X-rays)
  • Ultrasound (I always like to have my abdominal ultrasounds performed by a board-certified veterinary radiologist, called a Diplomate of the American College of Veterinary Radiology or “DACVR” for short) 

*Keep in mind that some of these blood samples should be done when your cat hasn’t eaten anything for 12 hours. So when in doubt, don’t feed your cat the night before—or the day of—a veterinary visit. (Please have water available at all times!)

Blood work findings seen with IBD in cats typically include a mild anemia and elevated white blood cell count, abnormal protein concentration, cobalamin vitamin deficiencies, and mild increases in liver enzymes. 

Advanced diagnostic tests

More advanced diagnostic tests to help confirm IBD include:

  • Aspirates of any enlarged lymph nodes or masses performed during ultrasound; these should be submitted for cytology
  • Endoscopy under general anesthesia for intestinal biopsies (typically done through a board-certified veterinary internal medicine specialist)
  • Exploratory surgery to perform full-thickness intestinal biopsies (this can be done at your veterinarian, but requires full-thickness biopsies!)

The latter diagnostics are more costly, but they are the most definitive way of diagnosing IBD. Ideally, surgery is best at confirming IBD, as it’s taking larger tissue samples. However, it’s slightly more invasive because it requires opening up the abdomen (just like a spay!). Endoscopy can also be considered, but it does not allow for full-thickness biopsies (which are really, really helpful for diagnosing IBD vs. cancer of the intestines). When in doubt, talk to your veterinarian or a board-certified veterinary specialist about your options and what works best for you, your cat, and your wallet.

What’s the treatment for IBD in cats?

So, if your cat was just diagnosed with IBD, how is it treated? Is it expensive for long-term treatment? Ultimately, the goals of treatment for IBD in cats may include:

  • A course of antibiotics to normalize the gastrointestinal bacteria (e.g., metronidazole tylosin) $
  • A course of dewormers to treat for gastrointestinal parasites $
  • Vitamin injections $
  • Dietary changes or modifications (potentially to a hypoallergenic diet, modified protein diet, or even a high fiber diet) to help minimize any hypersensitivities to food or help resolve the diarrhea $$
  • Corticosteroids (which have anti-inflammatory effects that suppress the immune system from “attacking” the gastrointestinal tract) $
  • Other drugs that have anti-inflammatory or immunosuppressive effects (e.g., sulfasalazine, etc.)  $

Depending on how your cat responds, he or she may need to be initially started on a short course of dewormer and an antibiotic, while also trying to gradually transition to a new hypoallergenic or modified protein diet. 


Diet is one of the most important aspects of management of inflammatory bowel disease in cats! Keep in mind that you can’t transition cats suddenly to new diets, as it has to be done gradually over several weeks. Once your cat is transitioned to the new diet, he should be fed only this diet trial for 8-12 weeks. That means no other snacks. No treats. No milk. Nothing else. This is very important during this trial period, as we need to make sure it’s the only protein that your cat is exposed to. This helps rule out a dietary allergy. 

Corticosteroid therapy

No improvement? Then your cat may need long-term corticosteroid therapy—typically with an inexpensive drug called prednisolone—but our goal is to get your cat down to the lowest effective dose possible (every other day to every third day, if needed). This does have some potential side effects, but is really important to help reduce the inflammation in the intestines. If your cat is started on a corticosteroid, please note that you can’t discontinue it acutely. When in doubt, never adjust the dose without talking to your veterinarian.

The most important thing to consider when treating a cat for IBD is that it’s not curable. But it’s treatable and needs to be monitored carefully with help from your veterinarian. Please note that IBD needs to be treated—there are some thoughts that untreated IBD can predispose a cat to intestinal cancer (e.g., specifically lymphoma) down the line, so we want to make sure your cat is healthy, happy, and treated appropriately! With IBD, be aware that occasional relapses can occur (which sometimes require hospitalization), and medication trials and adjustments may be necessary. That said, the prognosis for IBD in cats is fair to good, short-term.

Cover photo by Manja Vitolic on Unsplash

black and white cat with green eyes - what is inflammatory bowel disease in cats?