Diarrhea in Cats: Causes, Home Care and When to See a Vet

By Tailwisp Editorial TeamUpdated October 20, 20264 min read

Loose stool is one of the most common reasons cats see a vet. Most cases are mild, but diarrhea can signal a serious problem, and in small or sick cats it can cause dangerous dehydration within hours. Knowing what to watch for helps you decide when to wait and when to call.

What is diarrhea?

Diarrhea means stools that are soft, loose or watery, often passed more frequently than normal. It can come from the small intestine, causing large volumes of watery stool, or from the large intestine, causing small, frequent stools with mucus or fresh blood and straining.

Common causes

• Sudden diet changes. Switch foods gradually over a week.
• Food intolerance or allergy.
• Rich or inappropriate food. See can cats drink milk and can cats eat cheese.
• Parasites, including worms and protozoa. See worms in cats.
• Infections, viral, bacterial or parasitic.
• Stress, such as moving, new pets or travel. See moving house with a cat.
• Inflammatory bowel disease and other chronic conditions.
• Hyperthyroidism, kidney, liver or pancreatic disease.
• Toxins and foreign objects. See cat-proofing your home.
• Medications, such as some antibiotics.
• Cancer, particularly in older cats.

What the stool tells you

Take a photo and a fresh sample for your vet.

When to see a vet

Contact your vet the same day if there is:

• Blood or black, tarry stool
• Vomiting along with diarrhea. See cat vomiting causes.
• Lethargy, weakness or hiding
• Not eating, or not drinking
• Signs of dehydration, such as dry gums or skin that stays tented when lifted
• Abdominal pain or a swollen belly
• Fever
• Age under six months or over ten years
• Diarrhea lasting longer than a day or two
• Known access to toxins or foreign objects

See the emergency warning signs guide, and use the US vet directory to find a clinic.

Home care for mild cases

For an adult cat that is bright, eating and drinking, with a short bout of mild diarrhea:

• Provide fresh water at all times.
• Offer small meals of the usual food, or a bland diet if your vet advises it.
• Avoid treats, dairy and table scraps.
• Keep the litter box clean, and monitor stools.
• Do not give human medications such as loperamide or bismuth compounds, which can be toxic to cats.
• Call your vet if there is no improvement in 24 hours.

Do not fast kittens or cats with other conditions without veterinary advice.

Diagnosis

Your vet may do a physical exam, a stool test, blood work, X-rays or ultrasound. Treatment depends on the cause and may include dewormers, a diet change, probiotics, fluids or medication. See cat vet visit costs.

Diet and prevention

• Change diets slowly, mixing old and new over seven to ten days.
• Feed a complete and balanced diet. See how much should I feed my cat.
• Avoid human foods that upset cats or are toxic. See is chocolate toxic to cats.
• Keep up with parasite control and vaccinations. See the cat vaccination schedule.
• Reduce stress with routines and enrichment.

Chronic diarrhea

Diarrhea lasting more than two to three weeks is considered chronic. It needs a full workup to find the cause, such as food allergy, inflammatory bowel disease or other disease. Keep notes on stool frequency, diet and symptoms to help your vet.

Keeping a record

Write down when diarrhea started, how often it happens, what the stool looks like and any other signs, such as vomiting or reduced appetite. Note recent changes in food, treats, plants, stress and medication. Take photos and a fresh stool sample in a clean container. This information helps your vet find the cause faster, and it avoids unnecessary tests.

Probiotics and fiber

Some vets recommend probiotics or added fiber for mild or recurring problems, and prescription gastrointestinal diets exist for cats with sensitive digestion. Use only products your vet approves, since human supplements can contain ingredients that are not safe for cats. Return to normal food slowly once stools are firm, and watch for relapse.

Dehydration check

Gently lift the skin over the shoulders. In a well-hydrated cat it springs back at once. If it stays up or returns slowly, or the gums are tacky and the eyes look sunken, the cat is dehydrated and needs a vet quickly. Offer water, but do not force large amounts, and do not delay care while waiting for the cat to drink.

Kittens

Kittens can dehydrate quickly. Call your vet promptly, and see kitten feeding schedule and kitten litter training for context on normal habits.

This article is general educational information, not veterinary advice. Every cat is different. If your cat is unwell, or you are unsure about a symptom, diet change or medication, contact your veterinarian.