Kitten Diarrhea: Causes and Treatment

Kitten diarrhea at a glance

About: Diarrhea is the passage of loose and watery stools. Diarrhea is common in kittens, but should always be taken seriously as they can dehydrate quickly.


  • Dietary indiscretion
  • Milk (cows) consumption
  • Sudden change in diet
  • Protozoal infection (giardia, cryptosporidium,
    coccidiosis, Tritrichomonas fetus)
  • Viral infection (FIV, FeLV, rotavirus,
  • Bacterial infection (salmonella, e-Coli,
    Campylobacter, Clostridium)
  • Intestinal worms
  • Stress
  • Heatstroke
  • Poisoning (plants, food, chemicals, medications)
  • Fading kitten syndrome

Treatment: Observe kittens at home for 24 hours if they appear otherwise well. If diarrhea persists longer than that, or if your cat is exhibiting other symptoms such as lethargy, if he has consumed a toxin, loss of appetite or blood in the stool, seek veterinary attention
immediately. If possible, bring along a stool sample.

Prevention: Introduce new foods slowly. Keep toxins, poisonous plants, medications out of reach of your kitten.

Worm kittens every two weeks, from two weeks of age and vaccinate at 6-8 weeks.


Diarrhea is the passage of watery stools in kittens and cats. It is not a disease in itself, but a symptom of an underlying problem, and it may be the only symptom, or it may accompany other symptoms such as lethargy, vomiting, and loss of appetite.

Diarrhea in kittens one of the most common complaints seen by veterinarians. Their gastrointestinal system isn’t fully developed, and they are more sensitive to dietary changes, as their immune systems aren’t yet fully developed they are also at higher risk of catching infections or diarrhea-causing parasites such as coccidiosis.

Diarrhea can be acute or chronic. Acute diarrhea is the sudden onset of frequent watery stools; chronic is diarrhea that has been present for more than three weeks.


There are many causes of diarrhea, some of which can be life-threatening. Kittens in shelters are at particular risk of infectious diarrhea, with common pathogens including feline panleukopenia, giardia, and coccidia. Diseases such as FIV and FeLV can weaken the immune system making affected kittens more vulnerable to other bacterial, viral, fungal or protozoal infections.

Sudden change in diet

A common cause of diarrhea in kittens. Young cats, in particular, are susceptible to dietary changes, so when you bring your new kitten home, find out from the breeder, or the previous owner what the kitten has been eating so far. He should continue to have the same diet, but if you would like to change to a different type or brand of food, you can do so, but introduce it gradually, over several days. On the first day 90% old food, 10% new food, second day 80% old food, 20% new food etc. This will slowly accustom your kitten to the new food without upsetting his tummy.


Switch back to the cat’s previous diet and then make dietary changes slowly by gradually increasing the new food and decreasing the old type.


Kittens can develop diarrhea if they are fed one or two large meals which can upset the stomach.


Kittens have high caloric needs due to the amount of energy that goes into growing. However, it is better to feed several small meals a day instead of one or two large meals. This will help to resolve diarrhea due to overeating, or rushing meals.

Food allergies and food intolerances

Food allergies are an unlikely cause of diarrhea in kittens, which typically develop over time, however food intolerances such as giving them cow’s milk may affect kittens.


Once the problem food is discontinued, symptoms will resolve.

Dietary indiscretion

Eating something he shouldn’t have such as cat litter, food from the garbage bin or toxic plants may cause diarrhea, especially in kittens who are generally less discerning than adult cats.


This will depend on the food which has been eaten. If a toxin has been ingested, gastric decontamination may be necessary as well as administration of activated charcoal to bind to the poison. Also, the cat may be fed a bland diet and provided supportive care such as fluid therapy to correct dehydration.

Lactose intolerance from cow’s milk

Many new kitten owners think that kittens should drink milk. This is a common cause of diarrhea in kittens as they are unable to digest the lactose in the milk. If you want to give your kitten milk, purchase the “cat milk” available from most supermarkets.


This should resolve once the kitten is no longer allowed cow’s milk. If you do want to give your kitten milk, stick lactose-free milk for cats available in supermarkets and pet stores.


Salmonellosis is a bacterial infection caused by the Salmonella bacterium. It is a common cause of enteritis (inflammation of the intestines) with associated vomiting and diarrhea. Salmonella can affect a wide range of animals including humans, wild animals, domestic pets, farm animals, birds, fish, reptiles, and amphibians.


Direct contact with an infected animal or prey, contaminated food or via objects such as food bowls.


  • Symptomatic cats will receive fluids to treat dehydration and replace electrolytes.
  • Blood transfusion for severe cases where septic salmonella has developed.
  • It seems there is some controversy over the use of antibiotics to treat uncomplicated cases of salmonella enteritis (intestinal inflammation) with diarrhea in cats, suggesting that antibiotics can favour the growth of antibiotic-resistant strains of salmonella. Antibiotics (sulfa) are therefore reserved for severely ill cats.

Home care:

Supportive care at home for mild cases which may include a bland diet or restrict food for 24-48 hours.

Hospital care:

  • Symptomatic cats will receive fluids to treat dehydration and replace electrolytes.
  • Blood transfusion for severe cases where septic salmonella has developed.
  • It seems there is some controversy over the use of antibiotics to treat simple cases of salmonella enteritis (intestinal inflammation) with diarrhea in cats, suggesting that antibiotics can favour the growth of antibiotic-resistant strains of salmonella. Antibiotics (sulfa) are therefore reserved for severely ill cats.


Campylobacteriosis is an infection caused by the Campylobacter jejuni bacterium. It is associated with enteritis (inflammation of the small intestine), resulting in diarrhea. Kittens, particularly those under six months of age are most susceptible to infection due to their immature immune systems. The disease is zoonotic which means it can be passed from cat to human.


Cats can become infected via contact with an infected animal, contaminated water, feces, fomites (inanimate objects such as litter trays, toys etc.) raw meat, especially chicken.


Antibiotics will be prescribed to treat the infection.

Supportive care may be necessary, this can include fluids to replace lost fluids and correct dehydration, and a bland diet to rest the stomach while the cat recovers.

Isolate the affected cats from other pets to reduce transmission.

Escherichia coli

E. coli is a bacteria that usually resides in the gastrointestinal tract of mammals (including cats and humans) without incident. There are hundreds of strains of E. Coli, most of which are harmless. However, some strains are pathogenic, resulting in sickness.


Antibiotics are the treatment of choice along with supportive care which may include intravenous fluids to correct electrolyte imbalances and treat dehydration as well as nutritional support.

Newborn kittens are particularly at risk, and aggressive treatment is necessary if they are to survive.


A bacteria which is commonly found in the intestines causing no problems. It is not the bacteria that cause disease but toxins released by the bacteria (known as enterotoxins). Immunocompromised kittens are at the highest risk.


An infected cat sheds spores into the environment which go on to infect others.


Antibiotics, as well as aggressive supportive care, will include fluids to treat dehydration and nutritional support.

Feline Immunodeficiency Virus

Feline immunodeficiency virus (FIV or cat AIDS) is an infectious disease caused by an RNA lentivirus (slow-acting viruses) of the retrovirus family. It is in the same family as the feline leukemia virus (FeLV) and is similar to HIV in humans. FIV infects both domesticated cats, lions, tigers, pumas and cheetahs.FIV attacks the cells of the immune system, leading to FAIDS (feline acquired immune deficiency syndrome). This compromises the cat’s ability to fight off infections.


Bites are the most common mode of transmission.


Stages one and two

  • Regular veterinary check-ups. FIV-positive cats should see a veterinarian at least twice a year for check-ups.
  • Maintaining proper flea and worm control.
  • Feed a high-quality commercial diet is the best option for an FIV cat.
  • Maintain a proper vaccination regimen to protect your cat from other infectious diseases.
  • Keep your cat stress-free as stress impacts the immune system, avoid changes in the household, if you do have other pets, make sure resources such as litter trays, food and toys are plentiful.

Stage three

  • Blood transfusions if your cat has become anemic.
  • High-calorie supplements.
  • Fluids to treat dehydration, where necessary.
  • Antibiotics to prevent or treat bacterial infections.

Feline leukemia virus

Discovered in 1964, the feline leukemia virus (FeLV) is a retrovirus belonging to the subfamily orthoretrovirinae which is in the same family as the feline immunodeficiency virus (FIV). Currently, 2%-3% of cats who go outdoors in the United States are FeLV positive. The virus is neoplastic, which means it causes cancer, predominantly lymphoma, it is also immunosuppressive and bone marrow suppressive.


Saliva or respiratory secretions, during sexual intercourse, in utero, via the mother’s milk and fomites (inanimate objects).


There is no cure for FeLV, and treatment is usually targeted at managing FeLV-related diseases and keeping the cat as healthy as possible. Your veterinarian will tailor the treatment and care of the FeLV-positive cat according to its circumstances.

  • Regular check-ups with your veterinarian to carefully monitor your cat’s health.
  • Different vaccination schedules for the FeLV positive cat such as only using a killed vaccine instead of a modified live vaccine.
  • Interferon is a natural protein released by cells that have been invaded by viruses and assist the immune response by inhibiting viral replication.
  • AZT (azidothymidine) is an antiviral drug used in humans with HIV. It can produce quite severe side effects in cats. A veterinarian will need to monitor the cat.
  • Antibiotics to treat or prevent secondary infection.
  • Fluid therapy to treat dehydration.
  • Administration of vitamins and minerals.
  • Chemotherapy to manage lymphoma.
  • Keep the cat indoors, or with access to a safe cat enclosure.

Feline panleukopenia

A common viral infection caused which causes a low white blood cell count in cats which can lead to a secondary infection. Between 25 – 75% of infected cats die. It is seen most often in kittens, although cats of any age can become infected. In the host, it replicates in and kills rapidly dividing cells such as those lining the gut and the bone marrow resulting in a depletion of white blood cells and bacterial infection of the leaky gut wall. Cats of any age can be infected although it is most common in kittens and feral colonies.


Feces, urine, saliva or vomit of an infected cat or from fomites such as cat bowls and litter trays.


Antibodies usually appear within around 3 – 4 days of infection, so if the cat can be kept alive for this long, hopefully, the antibodies will be able to fight off the infection. Two days later there is a sharp rebound in the white blood cell count.

  • Blood transfusions if the white blood cell count drops significantly.
  • Antibiotics to fight off secondary bacterial infections which can develop due to decreased white blood cells.
  • Anti-viral medications (omega-interferon).
  • Intravenous fluids to correct dehydration and electrolyte imbalances.
  • Painkillers.
  • Medications to control vomiting.
  • Vitamin B and C injections.
  • Nutritional support (feeding tube).


A prevalent cause of diarrhea with a prevalence of between 4 – 12% in cats and kittens. The parasite infects the small intestine, producing voluminous, pale coloured and foul-smelling diarrhea but doesn’t contain blood or mucus. Giardia doesn’t generally cause loss of appetite or vomiting.


Cats become infected via exposure to an infective cyst shed in the feces of an animal with the parasite. This may be via eating or sniffing the feces of an infected animal or drinking contaminated water.


There are several medications available to treat clinically affected cats; however, no drugs been approved for the treatment of giardia in cats in the USA.

Flagyl (Metronidazole)

This medication also has the benefit of having anti-inflammatory properties also. Do not use in pregnant cats as Flagyl is suspected of being teratogenic (can increase congenital abnormalities). Side effects may include loss of appetite and hypersalivation due to the bitter taste of this medication.

Drontal Plus, Panacur (Fenbendazole)

An anthelmintic (an antiparasitic drug to kill worms) if concurrent infection with parasitic worms is suspected. Metronidazole and Fenbendazole may be used in conjunction with each other.

Furoxone (Furazolidone)

Antibiotic and antiprotozoal medication. Furoxone can cause vomiting and diarrhea and should not be used in pregnant cats.

In addition to medications to kill the parasite, supportive care may be necessary, which can include the following:

  • Fluids to treat dehydration and nutritional support. Try to encourage your cat to drink as much water as possible to replace lost fluids. If your cat is not drinking, your veterinarian may recommend Pedialyte which can help replace lost fluids and electrolytes.
  • A bland diet can help rest the cat’s gastrointestinal tract.


Cryptosporidiosis (or crypto) is the name of a protozoal infection affecting the small intestine and sometimes the respiratory tract of affected hosts. It is caused by single-celled parasites of the genus Cryptosporidium which infects a wide variety of vertebrates including cats, dogs, humans, horses, and livestock. Up to 15% of cats in the United States have been infected with Cryptosporidium at some point in their lives. Cats from shelters have a higher rate of infection due to often crowded conditions.


Infection occurs via the fecal-oral route. Once the oocysts have become infective in the environment, they infect their next host in several ways including drinking contaminated water or eating contaminated food, exposure to objects such as litter trays contaminated with oocysts and ingestion of oocysts during grooming.


There are no effective medications to treat cryptosporidiosis in cats. A cat with a healthy immune system will rid itself of the parasite in time.

Some veterinarians may prescribe antiprotozoal drugs to treat immunocompromised cats. These may include Tylosin, Paromomycin, Clindamycin, Azithromycin, and Fenbendazole.

Supportive care may be necessary which can include nutritional support and IV fluids and electrolytes to treat dehydration and anti-diarrheal medications.


A parasitic disease of the intestinal tract that is caused by the microscopic protozoan called coccidia which is acquired via direct contact with infected cystsThere are many species of coccidia, and each is infective in different animals. The species of coccidia that most frequently affect cats are Isospora rivolta and Isospora felis.

Most adults carry coccidia, but their immune system keeps it in check, some adults may, however, shed cysts in the feces. Symptoms most commonly affect kittens under six months of age. Stressed cats and those who have compromised immune systems are at the highest risk of developing symptoms.


Direct contact such as hunting and eating an infected rodent, or via exposure to infective oocysts from feces in the environment.


It is not possible to kill the parasite, but medications can be given which inhibit coccidial reproduction.

The usual treatment is with a sulfa type antibiotic such as sulfadimethoxine or Trimethoprim-sulfa.

Supportive care such as intravenous fluids to treat dehydration and nutritional support while the cat’s immune system clears the parasite.

Tritrichomonas fetus

A recently identified protozoal infection sometimes misdiagnosed as giardia. It affects the colon and end of the small intestine (distal ileum); infection occurs via direct contact with infected feces. Kittens, particularly those in shelters and crowded catteries are most at risk of infection. Diarrhea may come and go; it may contain blood and/or mucus.


Fecal-oral route during grooming, consumption of contaminated food or water, or via the environment.


Not all infected cats will require treatment. So far, one study has shown some success with the drugs ronidazole and tinidazole.

As with other protozoal infections, supportive care is often necessary to manage symptoms; this may include fluid therapy and nutritional support.


Hookworms are small, thin nematodes that are approximately 10 to 20 mm in length and are a common intestinal parasitic worm of dogs but can also infect cats. Kittens most commonly become infected either in utero or via their mother’s milk. Hookworms live in the duodenum, the first part of the small intestine, where they attach themselves to the mucous membrane using teeth-like hooks to feed on the blood. An adult hookworm can consume up to 0.1 ml of blood every day, changing their point of contact every 4-6 hours. A heavy infestation can lead to anemia.


There are many effective medications to treat hookworms, and your veterinarian will be able to recommend an effective product. Most worming medications come in two forms, either topical which is applied to the skin on the back of the neck or tablet form.

Severely infected kittens may require hospitalisation and blood transfusions to treat anemia.


There are two species of spaghetti-like roundworms to infect cats, both of which live primarily in the small intestine, feeding on the intestinal contents. Kittens usually become infected via their mother’s milk or the environment, although infection can also be acquired via hunting. Affected kittens often have a characteristic pot-bellied appearance as well as diarrhea, vomiting, which may contain worms, failure to grow and poor coat condition.


There are several effective medications to treat both species of roundworms. As they only work on adult roundworms, and not larvae or cysts. Therefore it is necessary to repeat treatment every two weeks as the larvae mature in the cat.

Popular medications include Revolution, Purina Total Care, Exelpet, Profender, Popantel, Panacur, Milbemax, Heartguard, Aristopet and Advocate.


Medically known as hyperthermia, heatstroke is a life-threatening medical condition in which the body’s internal organs (liver, kidneys, lungs, heart, and brain) begin to shut down as a result of elevated body temperature caused by high temperatures and humidity. It is caused by prolonged exposure to heat and/or activity in hot weather where the body is no longer able to efficiently cool itself down. Any cat can develop heatstroke; however, some are at higher risk. Heatstroke is a medical emergency that can lead to organ dysfunction, blood clotting disorders, coma, and death. It requires urgent treatment.


The mode of treatment will vary depending on the severity of symptoms but may include:

  • Controlled cooling to carefully bring the cat’s body temperature down to a safe level with lukewarm water and fans.
  • Volume (fluid) replacement with an intravenous crystalloid solution every few minutes until there is an improvement.

Manage secondary complications

  • Oxygen therapy will be given if your cat is having difficulty breathing.
  • Heatstroke can be associated with swelling in the throat, aggravating the problem. Your vet may give the cat a cortisone injection to treat this. [1]
  • Close monitoring for signs of kidney or liver failure or disseminated intravascular coagulation.


Kittens can be especially indiscriminate when it comes to what they chew and in many cases consume. Poisoning can also occur when a well-meaning pet owner self-administers medication that has not been prescribed (such as dog-flea treatments or over the counter painkillers).

Common cat toxins:

  1. Topical insecticides, especially dog flea products
  2. Household cleaners
  3. Antidepressants
  4. Lillies
  5. Insoluble oxalate plants (Dieffenbachia, Philodendron)
  6. Cold and flu medication
  7. Tylenol (paracetamol)
  8. Glow sticks
  9. ADHD medications/amphetamines
  10. Rat poison


This depends on the type of poison ingested but may include:

  • Induce vomiting with xylazine to prevent further absorption of the poison if the cat was exposed within the past two hours. This treatment is contraindicated if the cat has ingested a caustic substance, is too sedate or if the cat is predisposed to aspiration pneumonia.
  • Gastric lavage if inducing vomiting is not possible, your vet may choose to pump the stomach instead. Your cat will be put under anesthesia and a tube inserted into the esophagus and down to the stomach. Fluid is pumped down the tube and into the stomach, which is then removed by gravity.
  • Bathing the cat with warm water and liquid soap to remove dermal contamination.
  • Surgery or endoscopy may be necessary for cats who have ingested caustic substances or solid products such as metals which can not be removed via gastric lavage or vomiting.
  • Activated charcoal will be given after gastric decontamination to absorb the remaining poison. Contraindications include cats who are having seizures or cats who are too sedate, to avoid aspiration.


It may seem inconceivable to some, but cats are prone to stress just like people. They can’t verbalise how they are feeling the way we can and often suffer in silence or are labelled naughty or antisocial cats for their stress-related behaviour. Kittens can become stressed due to the change in surroundings as well as missing the comfort of their mother and siblings. This will generally resolve in a few days with plenty of tender loving care.


Avoid triggers such as changes to routine, lots of visitors in the early days. Provide your kitten with lots of love, food and play and he will soon come around. If diarrhea lasts for longer than a day, even if the kitten seems well, please see your veterinarian to rule out an underlying medical cause.

Fading kitten syndrome

Fading kitten syndrome is characterised by apparently healthy kittens who slowly or suddenly fade and die. Kittens, especially very young kittens in the first two weeks of life are very vulnerable, and up to 11% of kittens will die before they turn eight weeks old. The cause may be a congenital defect, infection, maternal neglect, blood type incompatibility, environmental conditions (too hot, too cold). Kittens can fade and die extremely quickly, so it is always important for the carer to keep a close eye on the kittens and how they are thriving. If they show signs of fading, urgent veterinary attention is necessary.


Treatment is aimed at addressing the underlying condition if one can be found.

  • Antibiotics to treat bacterial infections.
  • Treatment of parasites.
  • Fluids to treat dehydration.
  • Bottle or tube feeding.

Even with aggressive treatment, often kittens are too weak to pull through. It is incredibly important to seek veterinary attention the moment you see a kitten acting out of sorts. If several kittens die, it may be worth having a necropsy performed to see if a cause can be determined, especially if you plan to mate the mother again.


If the kitten appears to be well, is eating, drinking and playing, as usual, you may choose a wait and see approach. In the meantime, put him on a bland diet such as boiled chicken or Hills I/D (intestinal diet) to give the gastrointestinal tract a rest.
Kittens who have had diarrhea for longer than 24 hours need to see a veterinarian as diarrhea in kittens can be serious as they dehydrate much faster than adult cats. You should see your veterinarian without delay if the diarrhea is accompanied by the following symptoms:

If possible, bring a stool sample to the vet with you, this can help to diagnose the problem.

Your veterinarian will perform a complete physical examination of your kitten and obtain a medical history from you. Questions he may ask may include:

  • What food has the kitten eaten recently?
  • Accompanying symptoms?
  • How old is the kitten?
  • Is he up to date on his vaccinations?
  • Does he receive regular flea and worm treatments?

Diagnostic workup:

  • Fecal examination, culture, and flotation: A sample of feces is evaluated to look for worms, worm eggs, bacteria and cysts in the feces.
  • Baseline tests: A series of tests including biochemical profile, complete blood count, and urinalysis to check for underlying infection, dehydration, and anemia.
  • Urinalysis:   A test of the cat’s urine to check the kidney function and to determine how dehydrated your kitten is.
  • X-rays: To look for intestinal blockages and evaluate the organs such as the liver and kidneys.

Additional tests may be necessary depending on your veterinarian’s index of suspicion.

Home care

If the kitten is over 12 weeks of age, appears otherwise healthy and has no other symptoms, you can treat at home for 24-48 hours to see if diarrhea resolves.

Feed a bland diet:

  • Chicken breast poached in water
  • Continue to provide water

If your kitten has any additional symptoms such as vomiting, loss of appetite, lethargy, see your veterinarian immediately. Kittens can dehydrate fast which can very quickly become fatal.


Administer all medications as prescribed by your veterinarian and ensure you complete the entire course.

If you plan to change your kitten’s diet, do so gradually as they have very sensitive stomachs. Avoid giving your kitten cow’s milk.

Disinfect food bowls, floors, litter trays and bedding to kill pathogens and keep food and water bowls away from litter trays.


  • When you bring your kitten home, find out what the kitten has been eating and stick to that for the first few days.
  • Slowly transition kittens to new food to avoid stomach upset from new foods. Gradually add the new food while reducing the old food, this should take a week.
  • Only give fresh, clean drinking water to your cat. Do not allow them to drink from potentially contaminated sources.
  • If you are feeding a raw diet, only feed human-grade raw meat and store it correctly. Discard uneaten raw or canned food after 30 minutes.
  • Don’t give kittens food past its use-by date.
  • Make sure you follow your kittens’ vaccination schedule.
  • Worm your kitten regularly.
  • Treat your cat regularly for fleas. Fleas are capable of transmitting several diseases including tapeworm, plague, feline infectious anemia and cat-scratch disease.
  • Kittens are inquisitive and anything they can put in their mouth they will do so kitten-proof your home.
  • Kitten-proof your home. A kitten is very similar to a toddler; they can get into a lot of trouble in very little time. Store medications, household products, poisons and small objects your cat can easily swallow away from kittens.

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  • Julia Wilson, 'Cat World' Founder

    Julia Wilson is the founder of Cat-World, and has researched and written over 1,000 articles about cats. She is a cat expert with over 20 years of experience writing about a wide range of cat topics, with a special interest in cat health, welfare and preventative care. Julia lives in Sydney with her family, four cats and two dogs. Full author bio