Rectal and Anal Inflammation in Cats

Melissa Boldan, DVM
By Melissa Boldan, DVM on Jan. 31, 2024
A Scottish Fold cat sits with their vet.

In This Article


What Is Rectal and Anal Inflammation in Cats?

The rectum is the last part of the colon, where stool is stored until a cat has a bowel movement and the stool passes through the opening to the outside (the anus). If the rectum or anus becomes inflamed, it’s called proctitis.

There are several conditions that can lead to proctitis in cats. When the entire colon is inflamed, this is called colitis, a common condition in cats. Colitis proctitis means the colon, rectum, and anus are all inflamed. Proctitis alone (inflammation of just the rectum and anus) is less common.

Because the rectum has an important role in helping a cat absorb water and firm up their stool, it does not function properly when inflamed. This can cause a cat to have diarrhea.

The anus may turn red when it’s inflamed. This is because chronic diarrhea may lead to a condition called rectal prolapse, and when this happens, pink tissue from the rectum protrudes from a cat’s anus.

Fortunately, proctitis is rarely a medical emergency when addressed by a veterinarian within a few days. However, if your cat is experiencing lethargy, vomiting, weakness, or fever in addition to their proctitis, bring them to an emergency vet. Prolonged diarrhea can lead to significant dehydration and more serious illness, and potentially death. 

Symptoms of Rectal and Anal Inflammation in Cats

Common symptoms of rectal and anal inflammation in cats include:

  • Diarrhea

Causes of Rectal and Anal Inflammation in Cats

Rectal and anal inflammation can be caused by many things.


The most common cause of colon and rectal inflammation in young cats is parasites, like intestinal worms and protozoa.

Parasites Giardia or Tritrichomonas foetus can lead to chronic diarrhea and straining. This may irritate the lining of the rectum and make the anus inflamed and raw.


Bacterial, viral, and fungal infections can also lead to inflammation of rectum and anus. Campylobacter, clostridium, salmonella, and E. coli are all common bacterial agents that can irritate the lining of the large intestine. Feline parvovirus and feline coronavirus are viral agents that often lead to gastrointestinal inflammation and diarrhea.

Histoplasmosis is a fungal infection that can affect the GI tract in cats in the Ohio, Mississippi, and Missouri river valley regions.


Some cats may develop dietary intolerance or food allergies that lead to colitis proctitis. Allergies—usually to the protein source in the food—cause inflammation in the GI tract and subsequent gastrointestinal symptoms.

Foreign Body Ingestion

Occasionally, cats will ingest non-food items. Linear foreign bodies, like string, are especially enticing to young cats. The string-like objects can cause the intestines to bunch up and irritate the lining of the intestines. This can also occur when cats ingest sharp objects like animal bone shards, needles, or pins.

Inflammatory Bowel Disease

Underlying infections and allergies can lead to a chronic condition called inflammatory bowel disease (IBD).

While IBD more commonly affects the stomach and small intestine, it can also affect the large intestine. This can lead to colitis and proctitis. This condition is more common in middle-aged and older cats and its symptoms are similar to those of gastrointestinal lymphoma, which is the most common cause of intestinal cancer in cats.

How Veterinarians Diagnose Rectal and Anal Inflammation in Cats

To diagnose rectal and anal inflammation, your veterinarian will start with getting a thorough history of your cat.

Let your veterinarian know about any fecal abnormalities. They may ask the following:

  • How often is your cat having diarrhea? Is it small amounts, more frequently, or voluminous?

  • Is your cat straining when trying to have bowel movements?

  • Are they having fecal accidents outside the litterbox?

  • How long ago did the issue start?

  • How is their appetite?

  • Are they vomiting as well?

Additionally, let your vet know if your cat is allowed outdoors or does any hunting. Cats that go outdoors are more likely to be exposed to infectious diseases from other cats and to internal parasites from hunting. Also share if you have acquired any new cats and whether you use regular parasite prevention products.

Your veterinarian will then do a complete physical exam of your cat. They will palpate your pet’s abdomen and examine their anus.

They may recommend a fecal testing, blood work, and X-rays of your cat’s abdomen depending on their history. Sometimes additional testing—like an abdominal ultrasound or fecal PCR testing—is performed as well.

Treatment of Rectal and Anal Inflammation in Cats

Treatment will be based on the underlying cause of your cat’s inflammation.

If your cat has parasites, they may be prescribed anti-parasitic medications.

Bacterial infections are treated with antibiotics, and fungal infections with antifungal medications. Viruses often only require supportive care. This may entail fluid therapy and hospitalization if your cat has had prolonged or protracted diarrhea and has become dehydrated.

If your cat has ingested a string or another foreign body, surgery may be needed.

Diet trials are often helpful for cats with suspected food allergies. Special diets have novel (new) proteins or hydrolyzed proteins that are broken down to be so small that they don’t trigger an allergic response.

For example, Blue Buffalo® NP is made with alligator meat and Hill’s® Food Sensitivities d/d is made with venison, both novel protein diets. Hill’s® z/d and Royal Canin® HP are examples of hydrolyzed protein diets.

Cats affected by inflammatory bowel disease or GI lymphoma are often prescribed steroid medications to reduce inflammation in the bowel. Your veterinarian may also talk to you about vitamin B12 injections, as most affected cats are unable to properly absorb this vitamin from their diet.

If your cat has a rectal prolapse, it will need to be surgically replaced.

Recovery and Management of Rectal and Anal Inflammation in Cats

Recovery from rectal and anal inflammation is usually quick, following appropriate treatment. If your cat is undergoing treatment for colitis proctitis, closely watch all intake and their bowel movements for any abnormalities.

Contact your veterinarian if your cat has persistent diarrhea despite treatment, or if they stop eating, become lethargic, or begin vomiting.

Probiotics may be helpful if your cat had diarrhea caused by rectal or anal inflammation.

There’s always bacteria in stool, but GI disturbances can lead to an imbalance in normal, healthy bacteria in the gut. Probiotics may be helpful in some patients to restore healthy gastrointestinal flora. Products like Purina® FortiFlora and Nutramax® Proviable are good probiotic options.

Prevention of Rectal and Anal Inflammation in Cats

While some causes of rectal and anal inflammation are unavoidable, some conditions are.

Try to keep your cat from eating anything that is potentially harmful, such as foreign objects, rodents and other hunted prey, and human food. Keeping your cat indoors and avoiding exposure to community cats can reduce their risk of infectious disease.

If your cat does develop diarrhea, be sure to get them in to see their regular veterinarian within a day or two, rather than wait it out. Persistent diarrhea and straining can lead to secondary rectal prolapse and proctitis.

Rectal and Anal Inflammation in Cats FAQs

What does rectal prolapse look like in a cat?

Rectal prolapse looks like pink tissue protruding from the anus. Sometimes it’s just a small amount of fluffy pink tissue and other times you may see a tubular protrusion of fleshy pink tissue that extends several centimeters to inches. The tissue may be raw and readily bleed when bumped or dragged across surfaces, like carpet.

What are home remedies for swollen anus in cats?

A cool compress may be beneficial for an inflamed anus. Consider taking a soft washcloth, running it under cool water, and wringing it out. Alternatively, place the wet washcloth in the refrigerator for an hour prior to gently applying it to your cat’s backside, if tolerated.

Why is my kitten’s anus protruding?

If your cat’s anus is red and protruding, it may be inflamed. This may occur secondary to diarrhea or irritation if your cat is licking their backside a lot. If pink tissue is sticking out of the anus, they may be suffering from a rectal prolapse.

Featured Image: standret/iStock / Getty Images Plus via Getty Images


Cook A. Feline Infectious Diarrhea.  Topics in Companion Animal Medicine. 2008;23(4):169-176.

Mott J, Morrison J, eds. Blackwell's Five-Minute Veterinary Consult Clinical Companion: Small Animal Gastrointestinal Diseases.  Ch. 83. 2019.

Twedt D. Feline Colitis. World Small Animal Veterinary Association World Congress Proceedings. Veterinary Information Network. 2014.


Melissa Boldan, DVM


Melissa Boldan, DVM


Dr. Melissa Boldan graduated from the University of Missouri College of Veterinary Medicine in 2012. She initially practiced mixed animal...

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