My Gastrointestinal (GI) Tract Is Upset

March 24, 2026

IBD In Cats

By Nancy Kerr

 

Most people have probably heard of Inflammatory Bowel Disease (also referred to as IBD) in humans. Did you know that cats can also get it? “Inflammatory bowel disease (IBD) is actually a syndrome, despite being called a disease. It is caused by a specific reaction to chronic irritation of the intestinal tract. The inflammation is the body’s response to an insult, injury, or foreign substance.”¹ “The inflammatory cells infiltrate the walls of the gastrointestinal (GI) tract, thickening them and disrupting the ability of the GI tract to properly digest and absorb food. Cats of any age can be affected by IBD; however, the disease occurs most often in middle-aged and older cats.”²

There are various forms of IBD which are classified by their location in the body and the type of cells involved. Lymphocytic-plasmacytic enteritis (inflammatory lymphocytes and plasma cells invading the small intestine) and eosinophilic enteritis (infiltration of the eosinophils into the GI tract) are the most common types of IBD in cats. In some cases, “IBD may be accompanied by inflammation of other abdominal organs, including the liver and pancreas.”²

Causes

While the exact causes of IBD are unknown, “current evidence suggests that it arises from a complex abnormal interaction between the immune system, diet, bacterial populations in the intestines, and other environmental factors. Based upon similarities to IBD in people and dogs, genetic abnormalities of the immune system are also thought to play a role in feline IBD.”²

“While IBD appears to affect all ages and sexes, it may be more common in purebred cats. The average age reported for the development of disease in cats is 7 years. In cats, there is an association between inflammatory liver disease, pancreatitis, and IBD. This combination of inflammatory disorders is often referred to as triaditis. There may also be an association between severe IBD and intestinal tumors.”³

Symptoms

While IBD can involve any part of the gastrointestinal tract, it most commonly affects the intestines and/or the stomach. Common signs can include “weight loss, bloody stools, lethargy, and decreased appetite. While these signs can vary in severity and frequency, the predominant signs depend on which parts of the GI tract are affected.”² If a cat is experiencing chronic vomiting, the stomach is involved. This is the most common clinical sign of IBD in cats. If a cat has chronic diarrhea, the intestines are involved. Some cats, can experience both vomiting and diarrhea due to both areas being involved.

“If IBD lasts for more than a few months, poor appetite and weight loss are common. Some cats may develop a voracious appetite due to being unable to absorb the food they are eating. However, this must be differentiated from hyperthyroidism. Vomiting hairballs more than once a month is not normal, and shows an inability to pass hair through the GI tract. This may be a sign your cat could have IBD.”¹

Diagnosing

IBD can be difficult to diagnose, since many of the symptoms are similar to other diseases. Veterinarians will often use blood, urine, and fecal tests to rule out other diseases. This can also identify complications, such as low levels of protein or electrolytes. An abdominal ultrasound may be used to help to identify abnormal sections of the digestive tract. In some case, an endoscope can be used to see intestinal changes. An endoscope or surgery are required to obtain the tissue biopsies needed for the diagnosis of IBD.

A veterinarian may then recommend X-rays, or an abdominal ultrasound to check for “metabolic disease, feline leukemia, parasitic or bacterial infections, hyperthyroidism, and certain types of cancer. Intestinal lymphoma, a form of cancer, can be particularly difficult to distinguish from IBD in cats.”² They may also measure the levels of the B vitamins B12 and folate in the bloodstream,“ as IBD can hinder the absorption of these vitamins from the GI tract.”² A hypoallergenic food trial may also be tried to rule out any food allergies.

Treatment

First steps will generally involve treatment for intestinal parasites if this has not been done recently, as well as a combination of dietary adjustments and medication. Since there is no single best treatment, this will mean that several different combinations of diet or medication may be needed to determine the best therapy. “Metronidazole may be recommended along with dietary modification as the first medical therapy. The drug has antibiotic, anti-inflammatory, and antiprotozoal properties, and is usually fairly well tolerated, although some cats may lose their appetite when given this drug.”²

A cat may have to go on a food trial using hypoallergenic diets containing protein or carbohydrate sources that the cat has never eaten before. “Rabbit, duck, or venison-based diets are common initial choices. If symptoms do not improve with a hypoallergenic diet, the cat may benefit from diets that are high in fiber, low in fat, and easily digestible.”² It will be several weeks or more before an improvement after changing the diet. During this time cat should not be given any other sources of food such as table scraps, flavored medications, and treats.

If these treatments are not effective, “corticosteroids, which are potent anti-inflammatory and immune-suppressing agents, may be recommended, either alone or in combination with metronidazole. Cats should be monitored closely while they are on corticosteroids, as diabetes and immune suppression are among their potential side effects. Generally, cats tend to tolerate these drugs well as long as they receive them at an appropriate dose. Cats usually take corticosteroids orally, starting with a higher dose that is gradually reduced over several weeks.”²

If none of the treatments tried so far has been successful in controlling the symptoms of IBD,

“(M)ore potent immunosuppressive drugs, such as chlorambucil or azathioprine, may be necessary. These drugs can suppress production of white blood cells, red blood cells, and, less commonly, platelets, in the bone marrow. Any cats taking these drugs should be monitored carefully. As GI bacteria may play a role in the development of IBD, newer therapies include prebiotics, which are substances that promote certain bacterial populations, and probiotics, which are bacterial strains that promote GI health. The addition of soluble fiber, such as psyllium, to the diets of cats with inflammatory colitis may be helpful, and supplementation with folate or vitamin B12 should be provided if an affected cat is deficient in these B vitamins.”²

Most cats diagnosed with IBD will generally require long-term therapy. After a cat is treated for a few months, medication will be discontinued to see if the symptoms come back. If vomiting or diarrhea recurs, treatment is resumed. “If oral medications are difficult to administer, it may be possible to give periodic injections of a long-acting corticosteroid called methylprednisolone (Depo-Medrol). The disadvantage of long-acting injections is that once the medication is administered, it cannot be removed from the body if there are any problems.”¹

Prognosis

IBD can often be controlled so that affected cats are able to be healthy and comfortable. However, even with proper management, symptoms may appear and disappear. Keeping things under control requires strict following of dietary and medical therapies. Observant monitoring by the veterinarian and owner is also critical, so that any relapses can be assessed and the dosing of long-term medications can be adjusted. “Most cats do well for many years while others will require alterations in therapy every few months.”¹

“However, if your cat has no response to diet or corticosteroids, the prognosis is less certain. In these cases, further testing is suggested to see if an underlying disease can be identified. Some forms of IBD may progress to intestinal cancer. Chronic inflammation has been hypothesized as a cause of GI lymphoma in cats. Occasionally though, a cat will be able to stop drug therapy.”¹

 

Sources

1. Malcolm Weir, DVM, MSc, MPH; Ryan Llera, BSc, DVM; Krista Williams, BSc, DVM; Ernest Ward, DVM, Inflammatory Bowel Disease in Cats, 2025, Accessed 01/10/2026, https://vcahospitals.com/know-your-pet/inflammatory-bowel-disease-in-cats
2. Inflammatory Bowel Disease, April 2018, Accessed 01/10/2026, https://www.vet.cornell.edu/departments-centers-and-institutes/cornell-feline-health-center/health-information/feline-health-topics/inflammatory-bowel-disease
3. Alice Defarges, DVM, DACVIM, Department of Clinical Studies, Ontario Veterinary College, University of Guelph; Shauna Blois, DVM, DVSc, DACVIM-SAIM, University of Guelph, Ontario Veterinary College; Edward J. Hall, MA, VetMB, PhD, DECVIM-CA, Langford Vets, Bristol Veterinary School; Thomas W. G. Gibson, BSc, BEd, DVM, DVSc, DACVSMR, Department of Clinical Studies, Ontario Veterinary College, University of Guelph; Kelly D. Mitchell, BSc, DVM, DVSc, DACVIM, Toronto Veterinary Emergency Clinic, Disorders of the Stomach and Intestines in Cat, 08 2025, Accessed 01/10/2026, https://www.merckvetmanual.com/cat-owners/digestive-disorders-of-cats/disorders-of-the-stomach-and-intestines-in-cats