You should call the vet when your cat has diarrhea lasting more than one or two days, if the diarrhea is dark and bloody, or if it’s accompanied by a fever, vomiting, or loss of appetite.



Cat Diarrhea



Should I Take My Cat to the Vet for Diarrhea?


Cats are no strangers to upset stomachs and diarrhea. They love to eat things they shouldn’t like plants and plastic, get hairballs, and overeat if given the opportunity. 


Occasional cat diarrhea should not cause panic, but several circumstances warrant calling the vet and scheduling an appointment. Prolonged diarrhea in your cat lasting for more than 24 to 48 hours, regardless of age, can be dangerous to your cat’s health. Additionally, cat diarrhea that appears dark and bloody are signs of a more serious internal problem such as bleeding or parasites.


If you’re unsure that you should make an appointment, call the vet anyway. It’s always better to be on the safe side. The veterinarian or their assistant will listen to your cat’s symptoms and tell you whether or not you should make an appointment or visit an emergency vet



Cat Diarrhea



Cat Diarrhea Causes

Cat diarrhea is not a disease or sickness that exists in isolation. Instead, it’s a symptom that something else could be wrong. Why does my cat have runny poop? Diarrhea can be caused by several causes, from diet changes to internal parasites. 


Here are some of the leading causes that can lead to cat diarrhea:


  • Changes to their diet
  • Food intolerance or allergies like lactose intolerance
  • Medications or antibiotics
  • Viral or bacterial infections
  • Inflammatory bowel disease
  • Cancer
  • Worms or other internal parasites
  • Thyroid imbalance
  • Gastroenteritis


Cat Diarrhea


When to Be Worried


Diarrhea happens when the intestinal tract cannot absorb the normal amount of water from the stool before a bowel movement, which can stem from a number of causes, some of which are listed above. 


Prolonged diarrhea causes dehydration. Diarrhea lasting anywhere from 24 to 48 hours should not be a cause for concern unless you have diarrhea in a kitten or elderly cat.


If you’re wondering, “When should I take my cat to the vet for diarrhea?”, the answer depends on a few factors.


Regardless of the time span, if your cat’s diarrhea accompanies a fever, vomiting, or loss of appetite, you should contact your vet as soon as possible.




It can be difficult to determine if your cat has a fever. A common myth is that you can tell if they have a fever by feeling for a dry, warm nose, but this is false. The only way to know if your cat has a fever is to take its temperature using a rectal thermometer. 


Watch for these signs that your cat has a fever:


  • Lack of energy or activity, depression
  • Loss of appetite
  • Decrease in drinking
  • Decrease in grooming
  • Shivering
  • Rapid breathing
  • Vomiting


And, of course, diarrhea. A fever develops to fight off a sickness or disease and will typically measure around 102.5º F, but anything higher than 106º F risks damage to internal organs. 


Cats have an extremely low risk of contracting Coronavirus, but symptoms to watch for of COVID-19 in your cat include coughing, fever, and diarrhea.



Cat Diarrhea





There are two types of vomiting in cats: chronic and acute. 


If you’ve had a cat for any amount of time, you’re probably familiar with acute vomiting. Acute cat vomiting happens infrequently and usually follows when your cat overeats, consumes something toxic or harmful, or simply has an upset stomach. Chronic vomiting occurs when your cat throwing up occurs regularly and can be a symptom of an ongoing digestive problem.


Acute vomiting is not a cause for concern unless you notice blood or a coffee ground-like appearance in the vomit. Acute vomiting does become an issue, though, when a cat who typically doesn’t throw up begins puking multiple times in a short time span. 


Vomiting itself is a vague symptom, but it warrants a call to the vet if it accompanies diarrhea.



Loss of Appetite


A loss of appetite in cats can be indicative of some illnesses such as an infection or kidney failure, or it can be caused by something as simple as a toothache.


Either way, loss of appetite can be detrimental to your cat’s health. If they’re not eating, their body will begin to tap into their fat reserves. This can lead to a condition known as hepatic lipidosis, a precursor to liver failure.


If your cat has stopped eating and regularly drinking, accompanied by diarrhea, their body is heading towards dehydration and fatigue quickly and needs to be seen by the vet.



Cat Diarrhea



Cat Diarrhea Treatment


The treatment for your cat’s diarrhea will vary based on the cause. Your vet may prescribe a medication or treatment, or you may have to tackle the problem at home by changing their food and providing fresh water.


What do vets give kittens or cats for diarrhea? Treatments include:


  • Switching their food. If you’ve recently changed their brand or flavor of food, an ingredient in the new food could be upsetting them. Consider switching back to their old food and phasing the new food in gradually, or switching them to a highly digestible diet.


  • Since diarrhea causes dehydration, make sure that your cat always has access to fresh, clean water. You can also mix water in with canned food to increase their hydration.


  • Some types of diarrhea will respond to fiber supplementation, such as canned pumpkin or Metamucil. Both can be mixed into your cat’s food.


  • If internal parasites are causing diarrhea, your vet will recommend a deworming medicine and schedule.


  • If your cat has irritable bowel disease, your vet will recommend treating it with a special diet, vitamins, or medication.


If your cat has diarrhea, it may just be the result of an upset stomach and will pass within a day. If you have a kitten, elderly cat, or witness diarrhea lasting longer than 24 to 48 hours, then you should call your vet, especially if it’s accompanied by fever, vomiting, or loss of appetite.



Cat Diarrhea

Dr. Erin Downes VMD

Dr. Erin Downes graduated valedictorian from the University of Pennsylvania School of Veterinary Medicine in 1992. She and her husband, Dr. Jay Rowan are the owners of Paoli Vetcare | Main Line Vet & Animal Hospital.