7 Common Causes of Diarrhea in Cats and Kittens

Your cat's stool can tell you a lot about their health. A mushy, soft or runny stool could simply be a sign of an upset stomach, but it could signal something more serious. Understanding the causes of diarrhea in cats and kittens, and knowing when to contact your veterinarian, are important steps toward keeping your feline friend happy and healthy.

1. Diet

Changes in your cat's diet, like switching to a new food, can cause GI irritation that can in turn cause mild or temporary diarrhea. Cats are unable to digest dairy, so giving them a dish of milk or cream can also cause diarrhea. Food allergies could also be to blame.

2. Parasites

More common in kittens than in adult cats, internal parasites like roundworm or tapeworm can irritate the intestinal lining and cause severe diarrhea.

3. Infections

Both bacterial and viral infections can result in diarrhea in cats and kittens. Unvaccinated kittens are especially vulnerable to viruses like feline leukemia, panleukopenia, feline immunodeficiency virus and rotavirus.

4. Digestive disorders

Diseases and disorders affecting the digestive tract can cause vitamin deficiencies and other nutritional problems that can lead to loose stool and diarrhea.

5. Environmental stress

Just as with people, stomach upset leading to diarrhea in both cats and kittens can be caused by stress and anxiety. If you've moved to a new home, or added a new pet or a new person (or baby) to your home, this could be triggering your kitty's diarrhea.

6. Ingesting toxic substances

Some cats will eat anything, and this is especially true for curious kittens. Many common household chemicals and both house and garden plants are toxic to cats and may cause diarrhea if ingested.

7. Medication side effects

Diarrhea is often a side effect of many prescription medications used to treat cats, including antibiotics and pain relievers.

How to Recognize Diarrhea in Cats and Kittens

Cat and kitten diarrhea can take on different appearances and textures, each of which tell a story about your kitty's health. This chart can help you know what's normal and when to see your vet.

No stool/unproductive straining

• What it means: Severe constipation.
• What you should do: Keep an eye on your cat, and make sure they're getting enough water. If they go more than two or three days without passing stool, contact your vet.

Hard and pebble-like

• What it means: Mild constipation.
• What you should do: Try switching the type of protein you're feeding them, which might be easier on their stomach. Make sure they're getting plenty of exercise and minimize stress. And consider adding a probiotic supplement to improve gut health.

Smooth, slightly lumpy, shaped like a sausage

• What it means: A healthy gut.
• What you should do: No need to do anything different.

Slightly mushy but holding its shape

• What it means: Mild gastrointestinal (GI) irritation.
• What you should do: Keep an eye on the situation. If it doesn't get better after a few days, gets worse or is accompanied by other signs of illness, contact your vet for advice.

Watery or soupy

• What it means: Diarrhea
• What you should do: If you've got a young kitten, see a vet right away. If you've got an adult cat, wait a day to see if it gets better. If it doesn't, or if it's accompanied by other symptoms, see your vet.

Slimy mucous in the stool

• What it means: A possible parasitic or other type of infection.
• What you should do: See your vet.

Red blood in stool

• What it means: Irritation near the anus.
• What you should do: If there's a lot of blood, see your vet right away.

Black/tarry stool

• What it means: Bleeding in the GI tract.
• What you should do: Treat this like an emergency and see a vet ASAP.

Orange stool

• What it means: Possible indication of liver or gallbladder issues.
• What you should do: See your vet.

Yellow stool

• What it means: May be a sign of coccidia, a parasitic infection.
• What you should do: See your vet.

Green stool

• What it means: Possible acterial infection.
• What you should do: See your vet.

How to Treat Cats With Diarrhea

At the first sign of diarrhea, you can take these steps to provide your kitty with some relief. For diarrhea that's temporary and mild, this may be all you need to do.

Home treatments

• Provide plenty of access to fresh water. Dehydration is the biggest danger from diarrhea, especially for young kittens. Encourage them to drink often, and if necessary, add water to their food.
• Consider whether any recent dietary changes may be causing indigestion. If so, go back to what you were feeding them before, and then gradually introduce new food by mixing it in with the old.
• Pay extra attention. Make sure you're not feeding your cat or kitten any dairy products or allowing them to eat table scraps.
• Add fiber to their diet to help firm up stool. Try feeding your kitty one teaspoon to one tablespoon of plain, pureed pumpkin. Pumpkin also contains the compound cucurbitacin, which is believed to have some benefit in treating intestinal parasites.
• Try to pinpoint and, if possible, eliminate or mitigate any sources of stress in your cat's life. If the source of stress is unavoidable, cat pheromone diffusers or sprays might help relieve your kitty's anxiety and help them calm down enough for their digestion to return to normal.

Persistent and severe diarrhea will need to be properly diagnosed by a vet to determine the underlying cause and the correct course of treatment. Depending on the cause, here's what your vet may prescribe.

Veterinary prescriptions

• Prescription diet cat foods or probiotics. Your vet may recommend switching your cat to a prescription diet that's easier to digest and high in fibers that feed the good bacteria in your kitty's gut. Probiotics may also be prescribed. If food allergies are suspected, your cat may be placed on an elimination diet to help determine what's triggering the allergic reaction.
• Dewormer or antibiotics. If parasites are detected, your vet will most likely treat your cat or kitten with an oral dewormer. Antibiotics might also be prescribed to treat possible infections.

You can also talk to your vet about adding pumpkin to your cat's food, which provides extra fiber that may help firm up their stool. Hypoallergenic diets for cats and kittens with food allergies may also be something to consider.

Regardless of the cause, your vet may prescribe a cat-safe anti-diarrheal agent to slow or stop the diarrhea and provide your kitty with some relief. Although it might be tempting to give your cat anti-diarrheal medication from your medicine cabinet, over-the-counter anti-diarrheal made for humans contain ingredients that are not safe for cats. Severe cases of diarrhea, and diarrhea involving young kittens, may also require the delivery of intravenous or subcutaneous fluids to treat dehydration.

When Should I Take My Cat to the Vet for Diarrhea?

You should contact your vet if your cat's or kitten's diarrhea doesn't clear up in 24 to 48 hours, or if you notice blood or discoloration in their stool. You should also see your vet immediately if the diarrhea is accompanied by any of the following symptoms:

• Fever
• Appetite loss
• Loss of energy
• Panting
• Dry or tacky gums, a sign of dehydration
• Vomiting
• Weight loss
• Pain
• Foul-smelling stool

And keep in mind that it's always a good idea to contact your vet at any sign of health changes in your cat.

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Expert Reviewer

Dr. Kathy Wentworth, V.M.D.

Dr. Kathy Wentworth, V.M.D., has been caring for companion animals in Southern California for 22 years after graduating from the University of Pennsylvania's School of Veterinary Medicine. She grew up in Colorado and completed her undergraduate studies in Animal Physiology and Neuroscience at UC San Diego. Dr. Kathy furthered her passion as a veteran by becoming board certified as a Diplomate in Canine and Feline Practice by the American Board of Veterinary Practitioners (2010-2020).

Author Bio

Jean Marie Bauhaus is a novelist and freelance writer who has been writing in the pet health and wellness space since 2014.