Chronic Diarrhea in Cats

“My cat has runny poop all the time.”  

If this is a concern of yours, you’re in the right place. You’ll want to know what cat chronic diarrhea is, what causes it, what diagnostics to expect, and treatment options.  

In this article, you’ll learn everything a pet parent needs to know about chronic diarrhea in cats. 

What Is Chronic Diarrhea in Cats?

The color, consistency, and frequency of your cat's bowel movements are indicators of their digestive health and overall well-being. Cat stool should appear brown and well formed, easily scooped but not too firm.  

When the food your cat eats doesn’t spend enough time in the intestines, the absorption of nutrients, electrolytes, and water is diminished and it results in stool that is soft, mushy, liquid, or watery. This softer stool is called diarrhea. 

Chronic diarrhea is diarrhea that reoccurs frequently over time. It’s stool that is consistently softer than normal and continues intermittently or continuously for three weeks or longer. 

Chronic diarrhea affects cats of all breeds and ages and can have many causes.  

Kittens, senior cats, and cats that are immunocompromised are most susceptible to serious complications of chronic diarrhea and should be examined by a veterinarian as soon as possible. 

Small intestinal (small bowel) diarrhea and large intestinal (large bowel) diarrhea are two terms used to indicate what portion of the intestines is affected. 

In small bowel diarrhea, there is a larger volume of stool than normal. If blood is present in the stool, it will look black or tarry. 

In large bowel diarrhea, frequency is increased and there may be a smaller volume per bowel movement. If blood is present in the stool, it will look bright red. Cats with this type of diarrhea may strain to defecate. 

Symptoms of Chronic Diarrhea in Cats

Symptoms of chronic diarrhea in cats depend on the cause.  

If your cat has diarrhea (this may be soft-to-watery in consistency) that lasts longer than 24-48 hours, or if they are showing any of the following symptoms, they should be examined by a veterinarian as soon as possible. 

• Abnormal stool color (dark, tarry stool) 

• Fresh blood in the stool 

• Straining to defecate 

• Increased frequency of defecation 

• Weight loss 

• Increased or decreased appetite 

• Decreased energy level (lethargy) 

• Vomiting 

• Dehydration 

• Increased flatulence 

• Visible parasites in the stool 

Causes of Chronic Diarrhea in Cats

Common causes of chronic diarrhea in cats are: 

• Disease that affects the intestines or gastrointestinal system 

• Disease that affects another part of the body, and diarrhea occurs as a result 

Let's look a little deeper at these common causes.

Intestinal Disease 

• Inflammatory bowel disease (IBD) 

• Intestinal parasites (Tritrichomonas foetus, giardia, worms, cryptosporidium, coccidia) 

• Bacterial infections (E. coli, salmonella, Clostridium) 

• Viral infections (feline immunodeficiency virus and feline leukemia virus) 

• Food allergies 

• Vitamin deficiencies 

• Partial obstructions (foreign material, intussusceptions, or masses) 

• Abnormal digestion of food (protein losing enteropathy or pancreatic insufficiency) 

• Triaditis 

• Gastrointestinal lymphoma 

Nonintestinal Disease 

• Hyperthyroidism 

• Kidney disease 

• Liver disease 

• Diabetes 

• Cancer (lymphoma, mast cell tumors, adenocarcinoma) 

• Pancreatitis

How Veterinarians Diagnose Chronic Diarrhea in Cats

Keeping a detailed history of your pet’s bathroom habits can be very helpful in diagnosing chronic diarrhea in cats.  

This should include the length, appearance, and frequency of the diarrhea, and anything that seems to improve or worsen it. 

The following tests may be used to diagnose your cat’s diarrhea: 

• Blood work 

• Thyroid test 

• Fecal test 

• Urinalysis 

Depending on your cat’s symptoms and results of previous testing, your veterinarian may conduct or refer your pet for additional tests, such as  

• X-rays 

• Ultrasound 

• Endoscopy/colonoscopy 

• Biopsies (collected via colonoscopy or surgically) 

Treatment of Chronic Diarrhea in Cats

Treatment of chronic diarrhea in cats depends on its cause.  

Your vet will identify any underlying causes and will recommend specific treatments for nonintestinal-related diseases such as hyperthyroidism or diabetes, as well as those that are intestinal-related.  

Your cat may need digestive support medications or supplements such as probiotics or vitamin B12. 

Depending on your cat’s condition, your vet may recommend a diet trial.  

If your veterinarian suspects a food allergy, they’ll recommend a diet with novel or hydrolyzed proteins. A novel protein diet is a diet containing only proteins that your pet has never eaten before. A veterinary diet may also be needed. 

A diet trial typically lasts three to eight weeks. Pets should only eat that diet during this time.  

Currently available blood tests for food allergies in cats are not as reliable as a diet trial. 

What Should I Feed a Cat with Chronic Diarrhea?

Depending on test results, there are two main treatment options for cats with chronic diarrhea: 

• A low-fat/high-fiber diet. This is recommended for cats with uncomplicated pancreatitis, infections, mechanical obstructions, or thyroid disease. For thyroid disease, a thyroid-specific diet (like Hill's Prescription Diet y/d Thyroid Care Original Flavor Dry Cat Food) may alternatively be recommended. 

• A novel protein/hydrolyzed diet. This is recommended for cats with food allergies or other diet-responsive conditions, such as IBD. 

These are mostly prescription diets, so you’ll need veterinary approval. Ask your veterinarian what type of diet is best for your cat.  

Recovery and Management of Chronic Diarrhea in Cats

Recovery from chronic diarrhea in cats depends on the primary cause.  

In some cats, general changes in diet and digestive support may improve fecal firmness.  

Cats with diarrhea caused by specific issues such as intestinal parasites, unregulated diabetes, or thyroid disease can have their diarrhea resolved within weeks of treatment, while others may need lifelong therapy to control their symptoms.  

While the diarrhea itself may resolve, some of these conditions (diabetes, medically managed hyperthyroidism) will also require lifelong management. 

Are There Home Remedies for Cats with Chronic Diarrhea?

Cats with a chronic disease, senior cats, kittens, and pregnant cats should all be examined by a vet immediately after chronic diarrhea is noted.  

If your cat’s diarrhea contains blood and is accompanied by vomiting, weight loss, lethargy, or lack of appetite, take them to a vet immediately. 

For those cats that continue to eat well, have a good weight, and have normal energy levels, a few options are available for you to try at home: 

• Diet trial using an over the counter “sensitive stomach” food, such as Hill's Science Diet Adult Sensitive Stomach & Sensitive Skin Chicken & Rice Recipe Dry Cat Food 

• Fiber supplement or canned pumpkin 

• Feline-specific probiotics, like FortiFlora or Royal Canin Probiotics Digestive & Immune Health Powder Supplement 

If these options don’t help your pet's stool return to normal in a few days, or if additional symptoms arise, take your cat to your primary care veterinarian immediately. 

Never give your cat over-the-counter anti-diarrheal medications for humans, like Pepto Bismol and Imodium, without first asking your veterinarian. These medications can have severe side effects in pets if not used properly.