Everything you need to know about diarrhea in cats

Finding stinky, watery diarrhea in a cat’s litter box is familiar to pet parents everywhere. It is important for cat owners to educate themselves so they know what to do and when to seek veterinary care when their furry friends are suffering from loose stools. Read on if you have ever wondered.

• What are the symptoms of diarrhea in cats?
• What is causing my cat’s episodes of diarrhea?
• How do I know when to seek vet care for my cat’s diarrhea?
• Can diarrhea be prevented in my cat?

A short bout of mild diarrhea is common and often resolves on its own in healthy adult cats. However, diarrhea should not be ignored if it persists, recurs, when there are other signs of illness, or if it occurs in young kittens or cats with another health issue.

Diarrhea is classified as the occurrence of loose, watery stools in cats. Cats with diarrhea may also experience:

• Straining to defecate
• Increased urgency to defecate
• Increased frequency or need to defecate
• Increased or decreased volume of stools
• An abnormal color to the stool
• Fresh blood or mucus in the stool

Due to an increased sense of urgency, cats with diarrhea may have accidents outside the litter box. In addition, a small amount of red, fresh blood in the stool is common due to irritation of the colon or rectum.

Types of diarrhea in cats

You may be surprised to learn further characterization of diarrhea can help your vet determine the underlying cause. Diarrhea in cats can be categorized based on the length of time the symptom has been present. Diarrhea can be classified as:

• Acute diarrhea: Has been going on for less than 24-48 hours
• Chronic diarrhea: Recurring diarrhea over at least two weeks

Diarrhea may have slightly different composition depending on which section of the GI tract it originated from. Both acute and chronic diarrhea can be traced back to either the small bowel or colon. The origin of diarrhea has slightly different symptoms that assist veterinarians in determining a potential cause.

Diarrhea is a symptom rather than a condition of its own. There are many causes of diarrhea in cats, sometimes making it difficult to determine the underlying cause without further investigation. Some causes of diarrhea in cats are relatively harmless, while others can be deadly. In healthy cats, most bouts of mild diarrhea are due to eating something unusual or irritating and resolve on their own in 24-48 hours.

Sudden changes in diet

Cats do best on a nutritionally complete diet. Changing a cat’s diet is sometimes necessary, but doing so abruptly can irritate the digestive tract, resulting in diarrhea. When switching foods, it’s best to do so gradually, taking several days to make the change.

Cats tend to be more selective about what they eat than dogs, but sometimes feline curiosity results in dietary indiscretion. Counter surfing or ingesting another pet’s food, table scraps, garbage, or spoiled food can cause an upset stomach and diarrhea. This is why it’s important to keep tempting food and other items out of a cat’s reach, store their regular food properly, and pay attention to expiration dates.

Food allergies or sensitivities

Just like people, cats can have food allergies or sensitivities to certain ingredients in their food. Food sensitivities can develop over time and affect cats of any age. Diagnosing food intolerances can be difficult. The investigation process often requires feeding a highly restricted diet under the supervision of a veterinarian or animal nutritionist, followed by reintroduction of foods one at a time. The entire elimination and reintroduction process requires repeated monitoring and follow-up appointments to ensure your cat is safe and well throughout the experience. If you think your cat might have food allergies or intolerances, you can work with a virtual veterinarian to get your cat the nutritional support they need from the comfort of home.

Intestinal parasites

Intestinal parasites rarely cause symptoms in cats. However, when they do, diarrhea is among the most common. Internal parasites that may cause diarrhea in cats include:

• Tapeworms
• Roundworms
• Hookworms
• Coccidia
• Giardia
• Whipworms

Internal parasites are identified with a fecal test.  “A false negative on a fecal test is common, so not finding a parasite does not completely rule them out,” explains Dr. Jo Myers, a Vetster veterinarian. “It is not uncommon for a vet to recommend a broad-spectrum dewormer before doing a lot of diagnostic tests to rule out parasites as a potential cause of gastrointestinal symptoms.”

Bacterial or viral infections

Many infectious diseases in cats have diarrhea as a symptom. These diseases are most common in young kittens and unvaccinated cats. Other symptoms, such as vomiting, lethargy, and fever, often accompany diarrhea in cases of infectious illness. It is important to visit a vet when diarrhea occurs alongside other symptoms in order to rule out a viral or bacterial infection. Vaccinating a cat for every disease that can cause diarrhea is impossible, but keeping vaccines up-to-date can help prevent some of the most serious contagious diseases in cats.

Other health conditions

Underlying or chronic diseases can also cause diarrhea. These medical conditions may include:

• Metabolic diseases: Kidney disease, liver disease, pancreatitis, gallbladder inflammation
• Endocrine disorders: Addison’s disease, hyperthyroidism
• Cancer
• Inflammatory bowel disease
• Injuries or trauma

Identifying these underlying conditions involves diagnostic tests, such as a fecal test, blood work, urinalysis, and imaging. Sometimes diagnostics for chronic illness require repeat tests from different labs and clinics, which might be difficult for pet parents to follow. If you want more information or need help reading your cat’s test results, a veterinarian or vet technician can help.

Side effects of medication

Some over-the-counter or prescription medications can cause diarrhea as a side effect. Every cat reacts differently to medications, so it is not always possible to predict if their medication will cause a bout of diarrhea. Before giving your cat a new medication, discuss possible side effects with your vet and what to do if your cat experiences them.

In healthy adult cats, mild diarrhea that is not accompanied by other symptoms can resolve on its own within 24-48 hours. However, seek vet care right away if:

• Diarrhea lasts longer than 24 hours
• Other symptoms, such as vomiting, lethargy, or loss of appetite, accompany it
• Your cat has an underlying health condition
• There is digested blood or a large amount of fresh blood in the stool
• A young kitten is experiencing severe diarrhea

After consulting a vet, you can help your cat with diarrhea at home in a few ways. Provide access to plenty of clean, fresh water to combat dehydration. A vet may recommend fasting your cat, offering a bland diet, or changing their diet. Note: fasting a cat should only be performed under the guidance of a veterinarian, as it can be dangerous for the pet. Finally, vet-approved anti-diarrheal medications may help relieve the symptom. Never give a cat medications your vet has not approved.

Diarrhea is a common symptom of many conditions and cannot always be prevented. However, there are steps cat owners can take to reduce potential causes. Avoid sudden food changes or offering table scraps to your cat. Keep other foods and tempting non-food items, such as houseplants, away and out of reach. Always keep parasite prevention and vaccinations up-to-date and discuss potential side effects of medications with your vet. Finally, taking your cat to receive regular wellness exams and testing can help catch any underlying conditions before symptoms begin. If your cat is experiencing diarrhea, or you have questions about the causes of diarrhea in cats, you can make an online virtual care appointment to discuss your cat’s health with a Vetster online vet.

What do you give a cat with diarrhea?

Mild diarrhea in an otherwise healthy adult cat may pass on its own within 24 hours. Provide plenty of clean, fresh water to combat dehydration caused by water lost in loose stools. Placing extra litter boxes around your home can also help prevent accidents due to an increased urgency to defecate. Do not fast your cat, change its diet, or give medications without your veterinarian's approval.

When should I be concerned about my cat’s diarrhea?

A bout of mild diarrhea is not uncommon and may resolve on its own in an otherwise healthy adult cat. However, see a vet if diarrhea lasts longer than 24 hours, is accompanied by other symptoms, or occurs in a young kitten or a cat with another health condition. A small amount of fresh blood in diarrhea is normal due to irritation of the colon or rectum, but a large amount of fresh blood or the presence of digested blood in the stool is considered an emergency.

Why does my cat have diarrhea?

Diarrhea is a common symptom of many conditions. Common reasons for diarrhea in cats include suddenly changing their diet, dietary indiscretion, a food allergy or sensitivity, viral or bacterial infection, parasitic infection, or as a side effect of medication.

Is diarrhea in kittens dangerous?

Kittens are at an increased risk of infectious diseases that can be deadly. In addition, dehydration caused by diarrhea can occur rapidly in a small kitten. Visit a veterinarian right away if your kitten is experiencing severe diarrhea or diarrhea lasting longer than 24 hours.