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My cat has diarrhea. Should I worry?

My cat has diarrhea. Should I worry?


cat pooping

I’m not sure who is more unhappy when the cat has diarrhea: you or the cat.


Diarrhea isn’t good news for anyone, but is it actually something to worry about?


The good news is that, most of the time, cat diarrhea isn’t something to be alarmed about and quickly resolves on its own.


But it when it doesn’t, diarrhea in cats can be a sign of something more serious, and can be also dangerous on its own, just as symptom.


This post will tell you how to tell the difference between nothing-to-worry-about diarrhea, and something-to-worry-about diarrhea, and when to call the vet.


How do you know it’s diarrhea?


You might think you’ll know diarrhea when you see it, and probably you will. But just in case, here’s a quick rundown of what to look for.


But first, let’s discuss what normal cat poop looks like.


What does normal cat poop look like?


cat poop

Healthy cat poop is an earthy brown color. It should be log-shaped and about four to six inches long.


Healthy cat poop will be just juicy enough for litter to cling to it, but not so moist that it leaves anything behind if you’re picking it up from a hard surface. I’ll hope, for your sake, that you’re scooping it up from the litter box, and not the floor.


Healthy cat poop should be firm enough to hold its own shape, but not so hard that you can’t squeeze it. I don’t know who is squeezing cat poop, but if you did, it would have a little give, and it wouldn’t crumble.


What does cat diarrhea look like?


Cat diarrhea is watery poop that can be oddly colored and foul smelling.


Cat diarrhea is loose and has no particular shape. Cats who are suffering with diarrhea usually have more frequent bowel movements than is normal for them.


What are some signs that a cat has diarrhea?


kitten in litter box

The proof should be in the litter box, but cats can be pretty good at hiding problems. Outdoor cats may be pooping out in the wild, in which case you might not even know that your cat has diarrhea.


Some indoor cats are such meticulous poop coverers that tummy troubles can go unnoticed. But there are usually (or eventually) other signs that you shouldn’t ignore or attribute to something other than diarrhea.


Remember, that some inconsistency in cat poop is normal even in completely healthy cats. But these signs shouldn’t be ignored:



Before you get annoyed by a mess on a rug, ask yourself if poop accidents are normal for your cat. If they’re not, think “diarrhea,” not “the cat is mad at me.” By the way, cats never use pee or poop to be vindictive. Read about it in this post.

Dirty fur, especially on longhaired cats

If your cat’s back door is looking less spiffy than normal, if there is staining or soiling of the fur, then consider diarrhea as a cause.

Cat can’t “hold it”

If pooping seems to have become an emergency for your cat, consider diarrhea as a cause.

Cat is straining to poop

While straining can be a sign of the opposite problem: constipation, it can also be a sign of diarrhea.
cat diarrhea

The poop doesn’t look normal

If something is “off” about your cat’s poop, it might diarrhea. Some things to look for:
  • An increased or decreased volume of poop
  • The poop isn’t a normal color
  • There is fresh, red blood in the stool
  • There is darker, already-digested blood in the stool
  • There is mucus in or on the poop


How does diarrhea happen?


cat digestive system

In a cat’s digestive system, the colon is one of the last stops for food that is being digested.


It’s the job of the colon to take liquified food waste from the small intestine, and absorb all the remaining water and electrolytes from it. The colon also works with bacteria and enzymes to break down the most difficult-to-digest food particles and extract any remaining nutrients from them.


The colon’s other job is to form the feces and store them, until it’s convenient for the cat to poop them out.[1]


Diarrhea happens when the food waste moves too quickly through the cat’s system. Water, electrolytes, and some nutrition don’t get absorbed by the body the way they should.[2]


Is diarrhea dangerous for cats?


A quick, acute bout of diarrhea is unpleasant, but not necessarily dangerous. But after a day or two, it becomes something to worry about for two reasons:


Diarrhea is a symptom, not a condition

Diarrhea is a sign that something else is going on in your cat’s body. Some of the causes of diarrhea are relatively harmless and will resolve on their own in short order.
But diarrhea that persists can be a sign of something far more serious, and shouldn’t be ignored.

Diarrhea can cause serious health problems

If diarrhea goes on too long, it can contribute to malnutrition because food that your cat has consumed isn’t spending enough time in his digestive system. Diarrhea can also cause dehydration, metabolic issues, and an electrolyte imbalance.[3]
If diarrhea is severe enough, your cat may need to be hospitalized for IV fluid therapy.[4]


What usually causes diarrhea in cats


cat eating from the table

In most cases, diarrhea in cats will be short-lived and resolve itself.[5] Some common, relatively benign, causes of diarrhea in cats include:


A change in diet

Switching foods too suddenly can irritate a cat’s digestive tract.
If you have to change your cat’s diet, do it gradually. It should take days to switch from one food to another. Look for instructions about how to switch foods slowly in the section “How to transition to in a new cat food” near the bottom of this post.

A “dietary indiscretion”

I love this term. I could be accused of committing the occasional indiscretion myself.
Counter surfing, eating the dog’s food, eating table scraps or garbage, or consuming spoiled food could all contribute to tummy upset.
You know what to do:

More serious causes of diarrhea in cats  


Unfortunately, diarrhea is a symptom of many other conditions and can have many other causes. These do not resolve themselves and the diarrhea can become chronic. You will likely need the help of a vet to get to the bottom of chronic diarrhea caused by:


Food intolerances/allergies

Even if your cat has been eating the same diet since the day you brought him home, he could become intolerant or even allergic to an ingredient in whatever you’re feeding him.
Allergies and intolerances to food can cause inflammation in the gut, which could, in turn, result in diarrhea.[6]
Diagnosing food intolerances can be difficult and you’ll need the guidance of a veterinarian or animal nutritionist. It usually involves feeding a restrictive diet for a period of time and then slowly reintroducing foods, one by one.


sick catBacterial, viral, or parasitic infections can all irritate the GI tract.
Parasites include common protozoa like giardia, tritrichomonas, and coccidia, and intestinal worms, such as hookworms, roundworms, and whipworms.[7]
Infectious diseases, especially viral infections like feline panleukopenia (feline parvo), feline immunodeficiency virus (FIV), feline infections peritonitis (FIP), and feline leukemia virus (FeLV) are most common in young kittens and unvaccinated cats. They are usually accompanied by other symptoms, including vomiting, lethargy, and fever.
If your cat has additional symptoms along with the diarrhea, call your vet.[8]


Chemical toxins and ingestion of poisonous plants can cause diarrhea.[9]


Even medications prescribed by your veterinarian can have diarrhea as a side effect. These include NSAIDs, steroids, heart medications, asthma medicine, and anti-anxiety drugs.
Antibiotics, specifically, can wreak havoc on the gut by killing off helpful bacteria as well as disease-causing bugs.[10]

Bowel obstruction

cat with stringWhen a cat swallows something she shouldn’t: a broken piece of a toy, or commonly, a string, it can cause a blockage in the intestines.
While an inability to pass stool is a common sign of a complete blockage, diarrhea is a possibility, too, as liquid building up behind the blockage eventually leaks or explodes out from mounting pressure.
A bowel obstruction is a veterinary emergency. Read this post about linear foreign bodies for more information about obstructions.


Cats are sensitive beings who do not tolerate changes in their routines or environment very well.
A trip in the car can be stressful to cats. Adding a new person to the household, or a new cat or dog, can cause stress. Changing your hours at work can also disrupt a cat’s beloved routine.
Stress causes the release of hormones that can interfere with the gut’s delicate microbiome, resulting in diarrhea.

Serious disease

Almost any disease that causes inflammation in a cat’s body can cause diarrhea. These include:
  • Metabolic diseases, such as kidney disease, liver disease, pancreatitis, and gallbladder disease
  • Endocrine disorders, such as Addison’s disease and thyroid disease
  • Cancer
  • Inflammatory bowel disease
  • Neurological disorders
  • Immune system disorders.[11]


What can you safely try if your cat has diarrhea?

(*Note: As an Amazon Associate, I may earn from qualifying purchases.)


If your cat has just developed a case of diarrhea, and you want to do something to help, you can safely try:


canned pumpkin

Canned pumpkin

Pumpkin has a lot of fiber, plus other healthy nutrients like potassium, phosphorus, calcium, and vitamins A, C, and K. The fiber can help add bulk to the loose stool.
Make sure you’ve bought 100% canned pumpkin, not pumpkin pie filling, which has sugar, spices, and other ingredients that may be dangerous for cats (and may actually worsen diarrhea). This pumpkin puree is the kind of thing you’re looking for.
Give a tiny amount, only 1-4 teaspoons (measure!). Note that pumpkin can be used to help with constipation, too.[12]

Probiotics made for cats

Probiotics are live microorganisms that can help restore the balance of healthy bacteria in a cat’s intestines.
Purina FortiFlora is a powder that comes in little pre-measured packets that you can sprinkle on a cat’s food. It’s handy to keep some around the house for emergencies. You don’t want to have to first order it when your cat is already sick.
cat drinking from faucet

Fresh, fresh, fresh water

A cat in the midst of a flare of diarrhea needs to be drinking extra water to combat the potential for dehydration caused by the loss of water in loose poop.
Cats are notoriously fussy about drinking enough water even on a good day, so don’t give her any reason to refuse to drink now. Make sure her bowl is scrupulously clean and frequently refreshed with clean water.
Place the water bowl away from the food bowl. Cats seem to prefer to have their food and water sources separated. You can read about that peculiarity in this post.

Extra litter boxes

Put extra litter boxes around the home to help prevent accidents. It’s not going to help the diarrhea itself, but everybody is going to feel better about things when the cat – with or without diarrhea – is using the litter box.
Read this post to learn about how many litter boxes you should have even when the cat doesn’t have diarrhea, and where you should put them.

What you should never do when your cat has diarrhea


Don’t give any medications to a cat without consulting a veterinarian. Specifically:


pepto bismol

Do not give Pepto-Bismol or Kaopectate to cats ever

Pepto-Bismol and Kaopectate (in its current formulation) contain ingredients that are in the same class of drugs that aspirin is in. They’re all salicylates and they’re all poisonous to cats. Cats can’t metabolize salicylates the way dogs or humans can.[13]
These drugs can cause respiratory failure, hyperglycemia, bleeding problems, seizures, liver failure, anemia, and ulcers in cats.

Do not withhold food or fast your cat

People used to think that fasting helped “rest” a cat’s bowels but now we know the opposite is true. Cats’ intestines actually need nutrition to heal.[14]
Your vet might might recommend fasting a vomiting cat, but fasting should only be done under a vet’s supervision.
Withholding food from a cat for even a short period of time can quickly lead to a life-threatening condition called hepatic lipidosis.


When should you call the vet?


Call the vet when your cat has diarrhea and:


  • Your cat is a kitten or a senior. Call within 24 hours.[15]
  • Your cat has liquid or semi-liquid stool that has continued for 48 hours.
  • The diarrhea is bloody. Call immediately.[16]
  • The diarrhea has darker, digested blood in the stool.
  • Your cat has other symptoms, too, like vomiting, lethargy, or loss of appetite.
  • Your cat has another known, underlying health condition.


How will my vet diagnose the cause of diarrhea?


cat with vet

Chronic diarrhea in cats can be particularly vexing because it can have more than one cause, and thus require more than one treatment to resolve.


Some of the things your vet might want to do to help diagnose the cause of your cat’s diarrhea include:


  • Bloodwork
  • Bacterial cultures
  • X-rays to look for blockages
  • Ultrasound
  • Endoscopy
  • Fecal test
  • Urinalysis.


Be prepared to answer questions, too. Your vet will want to know:


  • When the diarrhea started
  • How frequently your cat is having bowel movements
  • What your cat’s poop looks like
  • If there have been any changes to your cat’s diet or environment.


Note what your cat’s diarrhea looks like


Use this table to help describe your cat's poop to your veterinarian.

cat poop chart


Note the color of your cat’s diarrhea.


Dark red or black

Dark red or black stool suggests that your cat’s upper GI tract was bleeding. The dark color indicates that the blood had time to be digested before it was pooped out.

Bright red

A bright red coloration within the feces or coating the feces could be a sign of lower GI tract bleeding.

Yellow or green

Yellow or green poop could just be an indicator of what your cat ate recently. Green poop, for example, might just mean that your cat ate grass. But green poop can also be a sign of gallbladder disease.
Yellow poop can be a sign of liver disease, zinc poisoning, bacterial infection, or a particular kind of anemia.[17]


Also note whether there appears to be a mucus film over the poop. Mucus-coated poop could indicate dehydration or a parasitic infection.


What might your vet prescribe a cat with diarrhea?


cat using litter box

Your vet may want to try conservative treatments first, as many cats respond well to them. They can support the cat’s body while it works to correct whatever the problem is that caused the diarrhea. You may never actually figure out why the diarrhea started.


If these treatments don’t work within a few days, further tests or more aggressive treatment may be needed. You vet might try:



If your vet suspects parasites, he/she might recommend trying a broad spectrum dewormer.[18]

A veterinary diet

If your vet suspects a gastrointestinal problem, he or she might recommend a prescription food. These foods have extra fiber to feed the good bacteria in your cat’s digestive system, and contain antioxidants to help a cat’s own immune system do the work of healing.[19]


Your vet may prescribe probiotics to help restore the balance of good bacteria in your cat’s gut.

Anti-diarrheal agents

There are prescription drugs that can help slow the movement of food and water through the gut, reduce spasming, or reduce inflammation.


What if my cat is vomiting, too?


Vomiting with diarrhea is a veterinary emergency. The conditions and diseases that can cause vomiting along with diarrhea can quickly become deadly, including:


  • A bowel obstruction
  • Ingestion of a toxin
  • Organ failure
  • Diabetic ketoacidosis
  • Addisonian crisis
  • Severe infection
  • Severe food allergies.[20] [21]


If your cat is vomiting and has diarrhea do not wait until Monday, or until morning, or until you come home from work to call the vet.


What if my kitten has diarrhea?


kitten in litter box

Diarrhea is even more common in kittens than in adult cats.


A kitten’s digestive system is just getting used to solid food so any little thing can cause tummy troubles. Kittens are also more vulnerable to intestinal parasites and other diseases because their immune systems aren’t fully developed yet.[22]


Kittens being the silly little things that they are, are more likely to eat something they shouldn’t. The most worrisome things are toxins and objects that could could cause an intestinal blockage.


Because a kitten’s body is so small, even a short bout of diarrhea can cause dehydration and weakness.


If diarrhea in a kitten persists for more than a day, take the kitten to the vet.


How to prevent diarrhea


cat eating plant

While there is nothing you can do to prevent all cat diarrhea, there are some simple steps you can take to prevent common causes of diarrhea:


  • Avoid keeping toxic houseplants.
  • Keep chemical toxins, like household cleaners and essential oils, away from cats.
  • Don’t feed table scraps to cats.
  • Don’t make sudden changes to your cat’s diet.
  • Keep cats up-to-date on parasite prevention and vaccinations.



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DAwn and Timmy
Dawn LaFontaine

Dawn LaFontaine is a lifelong animal lover who always seems to have a little pet hair in her keyboard. Her blog, Kitty Contemplations, helps cat guardians better understand and care for the special beings they share their lives and homes with. Her cat-products business, Cat in the Box, sells beautiful, well-made, and award-winning products that she designed to meet the biological needs of cats.




[1] Spielman, Dr. Bari. “Structure and Function of the Gastrointestinal Tract in Cats.” PetPlace, Accessed 18 June 2024.


[2] “Diarrhea in Cats: VCA Animal Hospital: VCA Animal Hospitals.” Vca, Accessed 12 June 2024.


[3] “Diarrhea.” Cornell University College of Veterinary Medicine, Accessed 10 June 2024.


[4] “Diarrhea in Cats: VCA Animal Hospital.


[5] “Diarrhea.” Cornell University College of Veterinary Medicine.


[6] ibid


[7] “Cat Diarrhea: What Owners Can Do to Help and When to Seek Veterinary Care.” AnimalBiome, Accessed 17 June 2024.


[8] “Everything You Need to Know about Diarrhea in Cats - Vetster.” Vetster Online Vets, Accessed 14 June 2024.


[9] “Diarrhea in Cats: VCA Animal Hospital.


[10] “Cat Diarrhea: What Owners Can Do to Help and When to Seek Veterinary Care.” AnimalBiome.


[11] “What Causes Cat Diarrhea and What to Do about It.” PetMD, Accessed 12 June 2024.


[12] “Can Cats Eat Pumpkin?” PetMD, Accessed 12 June 2024.


[13] “Cat Diarrhea Treatment: What to Give Cats with Diarrhea.” PetMD.


[14] “Cat Diarrhea: When Is It Serious and How Do I Stop It?” Pet Health Network, Accessed 17 June 2024.


[15] “What Causes Cat Diarrhea and What to Do about It.” PetMD.


[16] ibid.


[17] ibid.


[18] “Everything You Need to Know about Diarrhea in Cats - Vetster.” Vetster Online Vets, Accessed 14 June 2024.


[19] “Diarrhea in Cats: VCA Animal Hospital: VCA Animal Hospitals.


[20] “What Causes Cat Diarrhea and What to Do about It.” PetMD.


[21] “Addison’s Disease in Cats.” PetMD, Accessed 14 June 2024.


[22] “Cat Diarrhea: What Owners Can Do to Help and When to Seek Veterinary Care.” AnimalBiome.


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