From The Vet: Kitten Diarrhea

Causes, Symptoms and Treatment

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. 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 greater risk of catching infections or diarrhea-causing parasites such as coccidiosis.

Diarrhea is further categorized into acute or chronic diarrhea. Acute is the sudden onset of frequent watery stools, chronic is diarrhea which has been present for more than three weeks.

What are the causes of diarrhea in kittens?

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. The causes can loosely be broken up into dietary, infection, parasites and other.


There are several diet-related possibilities. Sudden switch in your kitten’s food is a very common cause of diarrhea in kittens. Young cats in particular are very sensitive 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 a period of 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.

  • Overfeeding. Kittens should be fed several small meals a day. Some kittens can develop an upset stomach if they are fed a large amount.
  • Food allergies and food intolerances. Food allergies are an unlikely cause of diarrhea in kittens, which typically develop over time. Food intolerances such as giving them cow’s milk may affect kittens. Dietary indiscretion. Eating something he shouldn’t have such as cat litter, food from the garbage bin or plants may cause diarrhea, especially in kittens who are generally less discerning than adult cats.
  • Cows 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.


Bacterial infections:

  • Salmonella – A common bacterial infection which may be acquired via direct contact with an infected animal or prey, contaminated food or via objects such as food bowls.
  • Campylobacter – A zoonotic bacterial infection which is seen most often in kittens under 6 months of age. Infection can be due to contact with an infected animal, water, faeces, fomites (inanimate objects such as litter trays, toys etc), faeces and raw meat, especially chicken.
  • Ecoli – A bacteria which commonly lives in the intestinal tract of animals without causing problems. There are many strains of ecoli, some of which are particularly pathogenic, causing disease.

Viral infections:

  • Feline Immunodeficiency Virus – This virus is similar to the HIV virus in humans, and as the name would suggest, the virus attacks the immune system, compromising the cat’s ability to fight infection and making them vulnerable to infection from other pathogens. The most common mode of transmission is via a bite wound or sexual intercourse, however kittens can also become infected in utero or via their mother’s milk. There is no cure for FIV although symptoms can be managed.
  • Feline leukemia virus – In the same family as the virus responsible for FIV, feline leukemia virus (FeLV) is a viral infection that is transmitted via the saliva or respiratory secretions of an infected cat, during sexual intercourse, in utero, via the mother’s milk, cat bites and from fomites. Infected cats have a compromised immune system making them vulnerable to secondary infection.
  • Feline panleukopenia – A common viral infection caused which causes a low white blood cell count in cats which can lead to secondary infection. Between 25 – 75% of infected cats die. Cats of any age can become infected, but it is seen most often in kittens. Transmission can be via the faeces, urine, saliva or vomit of an infected cat or from fomites such as cat bowls and litter trays.

Rotavirus Protozoal infections:

Protozoa are a group of single celled organisms many of which cause intestinal disorders in the hosts they infect.

  • Giardia is an extremely common cause of diarrhea with a prevalence of between 4 – 12% in cats and kittens. Cats become infected via exposure to an infective cyst shed in the faeces of an animal with the parasite. This may be via eating or sniffing the faeces of an infected animal or drinking contaminated water. 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.
  • Cryptosporidium a common cause of diarrhea in kittens and cats, this infection is similar to giardia in which cats become infected via ingestion of an infected cyst shed by a cat carrying the parasite.
  • Coccidiosis is another protozoal infection of the intestinal tract which is acquired via direct contact with infected cysts. Kittens are particularly vulnerable to infection due to their immature immune systems. Tritrichomonas fetus is a recently identified protozoal infection which is sometimes mis-diagnosed as giardia. It affects the colon and end of the small intestine (distal ileum), infection occurs via direct contact with infected faeces.

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. Protozoal infections in cats have the potential to be passed on to other pets as well as people in the house. So great care must be taken when caring for an infected cats.


  • Hookworms are small, think parasites which live in the small intestine of cats where they attach themselves to the intestinal wall and feed on blood and tissue. Kittens most commonly become infected either in utero or via their mothers milk. Black and bloody diarrhea can occur due to bleeding in the intestines, stunted growth and anemia may also develop.
  • Roundworms: There are two species of spaghetti-like roundworm 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.
  • Other: Heat stroke – Kittens are not as efficient at maintaining their body temperature as adult cats, and can quickly become overheated as a result.


  • Kittens can be especially indiscriminate when it comes to what they put in their mouth. Antifreeze, plants, medications etc.
  • Intestinal blockage (cooked bones, cat litter, wool, clothing etc), this will often also be accompanied by vomiting.
  • Stress – Moving to a new house can be stressful to a kitten.
  • Fading kitten syndrome – This occurs in very young kittens in the first two weeks of their life who appear otherwise healthy and suddenly become very sick and die. The cause may be a congenital defect, infection, maternal neglect, blood type incompatibility, environmental conditions (too hot, too cold).

There are many possible causes. If you have an extremely young kitten who suddenly becomes unwell, urgent and aggressive medical treatment will be required to save it.

How is diarrhea in kittens diagnosed?

If the kitten appears to be well, is eating, drinking and playing as normal, 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 his stomach a rest. Kittens who have had diarrhea for longer than 24 hours need to see a veterinarian. Kittens can dehydrate much faster than an adult cat, so diarrhea must be taken seriously.

You should see your veterinarian without delay if the diarrhea is accompanied by the following symptoms:

  • Dehydration
  • Blood in the diarrhea
  • Mucus in the diarrhea
  • Fever
  • Foul smelling and/or frothy diarrhea
  • Loss of appetite
  • Lethargy
  • Pain
  • Vomiting

Go to the vet

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 the vet may ask may include foods your kitten has recently eaten, accompanying symptoms your kitten may have, the age of your kitten, has it been exposed to other cats who are sick, has it been vaccinated, where you got the kitten, has it been treated for parasites such as intestinal worms?

In some cases, the cause may be apparent, if not, your veterinarian may wish to perform the following tests to determine a cause:

Fecal examination to look for the presence of parasites such as worms or protozoal infection. Fecal culture to look for the presence of bacteria. Fecal location is a test used to look for worm eggs or parasitic cysts in the faeces. A small amount of faeces is placed in a tube and a liquid salt or sugar solution is added. A glass cover is placed over the top and the sample is left to stand for 20 minutes. Eggs or cysts in the faeces will float to the surface, these can then be examined under a microscope. Baseline tests including complete blood count and biochemical profile to check for an underlying infection, dehydration and anemia.

Urinalysis 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 liver and kidneys. Additional tests may be necessary depending on your veterinarian’s index of suspicion.

How is kitten diarrhea treated?

Treatment depends on the cause and may include:

  • Withhold food: If the diarrhea is acute, and he seems otherwise well, your veterinarian may choose to withhold food for a day or so (for kittens that are over 8 weeks of age). Water is still to be provided.
  • Bland diet: Either after the fasting period, or in place of, food that is bland and low fat should be fed for a few more days. Poached chicken breast is gentle on the stomachs of cats who have had diarrhea and is usually the preferred choice.
  • Anti worming medication will be administered to treat worms. There are a number of products on the market to treat worms in cats.
  • Anti-parasitic medications to treat protozoal infections. Common medications include Metronidazole (Flagyl) and Furazolidone (Furoxone).
  • Antibiotics for bacterial infections.
  • Symptomatic and supportive care for viral infections while your kitten’s own immune system fights off the infection.

Your veterinarian may also prescribe antibiotics in this case which won’t kill the virus but may hold off secondary bacterial infections which can sometimes develop. Anti-diarrhea medications may be prescribed to relieve symptoms.

Surgery may be required if the cause is an obstruction. Supportive care may be necessary while your kitten recovers from diarrhea. Treat dehydration and electrolyte imbalance if necessary. This may involve a short stay at the vet on an IV drip or he may choose to give your kitten some fluids subcutaneously (via injection under the skin). Nutritional support if your kitten isn’t eating.

FIV and FeLV can not be cured but symptoms can be managed in a number of ways. Anti-viral drugs such as AZT may be prescribed, regular veterinary visits to monitor his health, keeping up to date on parasitic treatments, feeding a high quality diet can all be of help in reducing the symptoms of FIV. Blood transfusion may be necessary in cats with late stage FIV. Panleukopenia is managed by treating symptoms and may include blood transfusions, fluids, and antibiotics to fight off secondary infections.


Administer all medications as prescribed by your veterinarian. Kittens do have very sensitive tummies, it is recommended that dietary changes be implemented slowly over a period of days and avoid giving your kitten cow’s milk. Keep all medications, poisons and small objects which can potentially be swallowed away from kittens.

It really is no different to having a toddler, they can and will get into anything if given the chance. Environmental decontamination of floors, food bowls, litter trays and bedding should also be carried out to kill infectious pathogens. Food and water bowls should be kept well away from litter trays.

Preventing diarrhea in kittens

  • 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 make sure it is stored properly.
  • Don’t give kittens food which is past its use by date.
  • Make sure you follow your kitten’s vaccination schedule.
  • Worm your kitten regularly.
  • Treat your cat regularly for fleas.
  • Most flea medications are administered monthly and come in topical or tablet form. Fleas are capable of transmitting a number of diseases including tapeworm, plague, feline infectious anemia and cat scratch disease.
  • Kittens are extremely curious and anything they can put in their mouth they will do so. Make sure your house is kitten proofed and don’t leave things lying around which your kitten could chew on. Keep all medications in a locked cupboard.
  • New kittens should be slowly transitioned to new food as sudden chances can cause an upset stomach. Kitten proof your home. A kitten is very similar to a toddler, they can get into a lot of trouble in very little time. Keep medications, household products, small objects which can easily be swallowed and houseplants away from kittens.