Why Do Cats Get Diarrhea?

Cat Diarrhea

Callie Harris, DVM, Nestle Purina Pet Care


Cats master the picture of good health so it’s hard to tell when an illness is serious. Cat diarrhea is one of those conditions. Acute diarrhea is common and can be self-limiting but If it lasts longer than 24 hours it may be a sign of a health problem and the diarrhea may require medical treatment.

What causes diarrhea in cats?

Most cat parents have had to deal with gastrointestinal issues, often resulting in diarrhea. It’s important to know that cat diarrhea is not a disease, it’s a sign of an underlying health issue or disease. A cat exhibits only two forms of diarrhea that will either be acute (sudden) or chronic (ongoing).

Acute Diarrhea causes:

  1. Dietary indiscretion
  2. Stress
  3. Toxin
  4. Viral, bacterial, or parasitic infection
  5. Rickettsia or flea-borne spotted fever
  6. Ingesting foreign bodies
  7. Medications such as laxatives or even some antibiotics
  8. Chemotherapeutic drugs
  9. Non-gastrointestinal systemic disease (such as liver, kidney, or heart disease)

Chronic Diarrhea Causes:

  1. Food allergy
  2. Intolerance to macronutrients in food, e.g.: carbohydrates
  3. Bacteria & Small Intestine Bacterial Overgrowth (SIBO)
  4. Parasites
  5. Pancreatic exocrine insufficiency
  6. Neoplasia/cancer
  7. Non-gastrointestinal systemic disease (such as liver, kidney, or heart disease)

What are the signs of diarrhea?

Diarrhea in cats can be a passing condition that may resolve within 24 hours depending on the cause. As a pet parent, it is important to observe your cat’s behavior during the day and contact a veterinarian as soon as possible if symptoms worsen.

A veterinarian may determine either small bowel or large bowel issue causing diarrhea, depending on which of the following symptoms the cat is presenting.

Small bowel symptoms of diarrhea in cats:

  • Weight loss
  • Poor body condition
  • Vomiting
  • Borborygmus, better known as an intestinal rumbling
  • Excessive gas

Large bowel symptoms of diarrhea in cats:

  • Mucous blood
  • Severe cramping
  • Abdominal discomfort
  • Straining to poop
  • Tenesmus (rectal cramping to evacuate the bowel, even when it’s empty)

Which type of diarrhea does your cat have?

There are many causes of diarrhea in cats. Most pet parents are familiar with only the watery or liquid-like cat diarrhea. There is more than one type of cat diarrhea that can affect healthy intestinal function.

To evaluate the health of a cat’s gastrointestinal system, veterinarian measure consistency against a fecal scoring chart.

Cat diarrhea is determined as a result of an inability to absorb electrolytes to sufficiently regulate and maintain cells. The loss of nutrients, water, and chemicals cause fecal material to move through the intestine too quickly.

When a cat has diarrhea, it may be a one-off sign of a gastrointestinal issue or one of many symptoms that there is a bigger health problem.

Type of condition Main cause of diarrhea How it affects cats
Parvovirus, Corona Virus Intestinal inflammation
    Fluid loss
    Small intestine protein-loss
IBD, cancer NSAID, infectious agents Epithelial cells
    Lymphatic and blood vessels
    Immune system
Parvovirus, IBD, viral enteritis Disease Abdominal pain
Salmonella Bacterial infection Hormones
    Bacterial enterotoxins
    Some medications
    Deconjugated bile acids
    Hydroxyl fatty acids

When to call a veterinarian?

The most obvious sign that your cat is experiencing a medical issue is her change in behavior over 24 hours.

If your feline’s condition includes any of the additional symptoms in the list below, as well as, cat vomiting and diarrhea, it’s recommended that a veterinarian examines her as soon as possible.

  • Your cat is less than six months old or a senior cat aged 8+.
  • There is a pre-existing condition such as diabetes, or kidney disease.
  • Experiences labored breath
  • Passing runny stools more than 5 times a day.
  • Vomiting, or retching frequently or more than 3 times in 24 hours.
  • Blood in the stool.
  • Mucus film or oily-looking
  • Weight-loss or extreme tiredness.
  • Dull coat and dehydrated.
  • Depressed or showing signs of pain.

Never medicate a cat using drugs or medicine made or prescribed for people, unless directed by a veterinarian. To ensure your cat is nursed back to full health, consult with a veterinarian.

6 Easy ways to prevent diarrhea

  1. Be aware of the precautions of a raw food diet that may contain Salmonella.
  2. When choosing to switch your cat’s diet, transition over 7 to 10 days to avoid intestinal upsets.
  3. Table scraps and other food sources not part of a regular diet can cause irritation in the bowel.
  4. Birds, mice and other small animals that cats come into contact with may carry disease or infections.
  5. Keep your cat’s vaccination schedule up to date.
  6. Feed her a whole body, nutritionally-balanced diet. Some cats require a cat food diet for sensitive systems.

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