Kitten Diarrhea

By Jamie Case, DVM on Feb. 24, 2023

At some point, most kittens will experience diarrhea. It may range from a mild case with one or two incidents to a more severe case with multiple, frequent episodes of watery diarrhea.

Diarrhea can be a serious medical condition for kittens because their bodies aren’t as well-equipped to handle diarrhea as adult cats. They can quickly become dehydrated and malnourished.

It’s important to monitor your kitten closely and work with your veterinarian to determine the most appropriate steps. Here’s what you need to know about diarrhea in kittens.

Why Is My Kitten Having Diarrhea?

There are many potential causes of diarrhea in kittens, and it’s impossible to identify the cause based on the appearance of the diarrhea. Looking at a kitten’s age, history, and what has been going on may help narrow down the potential causes.

Common causes of kitten diarrhea include:

Bacterial Infection

Various bacterial infections can cause diarrhea in kittens. This includes bacteria that are normally found in a kitten’s intestines but grow out of control, as well as bacteria from the environment.

Escherichia coli (E. coli): E. coli (also known as colibacillosis) are bacteria found in the intestines. When kittens are stressed or ill, E. coli can multiply. It can also be picked up from various food sources and the environment. Young kittens may be exposed to E. coli in an overcrowded, dirty environment, or by their mothers if they are battling an E. coli infection due to the stress of pregnancy and raising kittens. In kittens under 2 weeks of age, you may see sudden bouts of watery diarrhea along with vomiting, lethargy, weakness, or sepsis. In older kittens, E. coli typically manifests as a sudden onset of diarrhea with vomiting and decreased appetite. Kittens with E. coli can quickly become dehydrated and should be seen by a veterinarian right away.
Salmonella: Salmonella infection is more likely to occur in cats and kittens that are stressed, in an overcrowded environment, or on a raw diet. Kittens suffering from salmonella may have bloody diarrhea with mucus, vomiting, decreased appetite, and a fever. These kittens may also be straining to defecate and seem like they have a stomachache.
Clostridial enterotoxicosis: This is caused when the Clostridium perfringens bacterium that’s normally found in the intestines overgrows due to stress, antibiotics, raw meat, or illness. It can cause diarrhea with mucus and traces of blood, and you’ll often see your kitten straining to poop. Infections may get better within a week, or they can flare up every couple of weeks.
Yersinia: Kittens may be exposed to Yersinia enterocolitica after eating raw or undercooked meat. Affected kittens may poop more often and strain to poop.
Campylobacter: Campylobacter is not a common cause of diarrhea in kittens, and it tends to affect kittens under 6 months of age that have other issues, such as intestinal parasites or a suppressed immune system. It is sometimes seen in kittens eating a raw diet. It may cause chronic diarrhea that can range from watery to bloody, with or without mucus. Affected kittens will strain to defecate and may also have less of an appetite or occasional vomiting. Campylobacter may be treated with antibiotics and supportive care on an outpatient basis, but if your kitten is very young or severely ill, more aggressive treatment might be needed (IV fluids, antibiotics, gastrointestinal protectants, and a bland diet).

Viral Infection (FIV, panleukopenia, FeLV, rotavirus)

Viral infections can also lead to diarrhea and gastrointestinal upset in kittens. Many of these can be prevented with routine vaccination.

Feline panleukopenia virus (FPV), often called feline parvovirus, is a highly contagious virus that can cause diarrhea and gastrointestinal upset in kittens. It is common in kittens that are 2-4 months old, but it can happen at any age. The virus is very resilient and can survive for years in the environment. Symptoms typically include sudden diarrhea along with vomiting, refusal to eat, and lethargy. Kittens with FPV quickly become dehydrated and require supportive care.
Feline herpesvirus or feline viral rhinotracheitis (FVR) can also result in diarrhea in young kittens. Cats catch this from other cats or from objects that have been exposed to an infected cat’s saliva or eye or nasal discharge.
Feline calicivirus (FCV) is another potential viral cause of diarrhea in kittens, which more often results in upper respiratory illness.
Rotavirus can result in diarrhea in cats and kittens and it can be transmitted to humans, so be sure to wash your hands well when handling kittens with diarrhea and cleaning up after them.
Feline leukemia virus (FeLV) is often transmitted to kittens from their mothers or other cats, although symptoms may not be visible for months or even years. It is spread through grooming and fighting. In rare instances, it can even be spread by shared food dishes and litter pans. In the early stages, most cats with FeLV will not show any signs, but as the disease progresses, they can have persistent diarrhea that is usually caused by other types of infection (bacterial, fungal, or parasitic). It may also cause other issues in infected cats, such as enlarged lymph nodes, upper respiratory tract infections, inflammation of the gums and mouth, and predisposition to certain cancers.
Feline immunodeficiency virus (FIV) is often transmitted between cats via bite wounds, but it may also be transmitted from mother cats to their kittens around the time of birth. Similar to FeLV, FIV often results in persistent diarrhea caused by bacterial, fungal or parasitic infection. It tends to cause more clinical signs in adult cats than in kittens.
Feline infectious peritonitis (FIP) can show up with various clinical signs. In some instances, it will cause stunted growth, decreased appetite, and chronic diarrhea in kittens.

Intestinal Parasites

Intestinal parasites, or worms, are common in kittens. Kittens can get worms even if they are strictly indoors, have had a stool sample taken before, and/or have been dewormed in the past. Similarly, you may not be able to see worms in the feces, so even if you don’t see anything, you can’t rule out intestinal parasites.

Some of the more common parasites that affect kittens include:

Roundworms have a spaghetti noodle-like appearance and can spread to kittens from eggs in the environment or while the kitten is still in their mother’s womb. Roundworms may cause diarrhea, vomiting, and weight loss. Affected kittens may look like they have a full, bloated belly.
Hookworms are smaller worms that can cause diarrhea, dark and tarry stools, constipation, weight loss, decreased appetite, and even a dry cough. They can infect kittens before they are born or may be picked up from the environment.
Tapeworms often have a “cucumber seed” appearance and infect kittens after they eat an infected flea or a small mammal, bird, amphibian, or reptile. Most kittens with tapeworms won’t show many signs of illness, but there may be some diarrhea, weight loss, and itchiness around the rectum.
Whipworms are small worms that may cause bloody diarrhea with mucus, weight loss, dehydration, and anemia. Whipworms in the environment may infect your cat and cause symptoms even before eggs show up in their feces.
Giardia is an intestinal parasite that can cause heavy diarrhea in kittens. The diarrhea may be intermittent or chronic and may have a strong odor and soft, greasy appearance. Giardia is typically found in water sources. Kittens that come from catteries, shelters, or other densely populated areas are more likely to have issues with giardia.
Tritrichomonas foetus can cause diarrhea in kittens and often causes symptoms that are very similar to giardia. Kittens with trichomoniasis may have issues with chronic or intermittent diarrhea. The diarrhea may have a strong odor and a soft and greasy appearance, and the kitten’s rectum may be red, painful, and swollen. It is not uncommon to see the diarrhea improve after being treated with antibiotics only to come back after antibiotics have been finished. Tritrichomonas foetus is more common in kittens from densely populated areas, such as shelters or catteries.
Coccidia may cause diarrhea as well as vomiting, decreased appetite, and abdominal pain. The diarrhea may be watery with mucus or blood-tinged. It often occurs during times of stress (weaning, moving to a new home, changing diets). Most of the coccidia bacteria that cause diarrhea and gastrointestinal upset in kittens are species-specific and only affect cats, but Cryptosporidium can be transmitted to other species, including humans.
Toxoplasmosis can result in diarrhea, vomiting, and decreased appetite in kittens. Depending on how a kitten got toxoplasmosis, a variety of other signs can be seen. Toxoplasmosis can spread from cats to people, so using good hygiene when cleaning up kitten feces is a must.

Stress

Stress can wear down a kitten’s immune system and cause diarrhea. Your kitten could be under stress from an infection, changes in their living situation, such as moving to a new home or a new pet being introduced, or simply from weaning.

A Change in Food

Switching to a new food too quickly or getting too many new treats can cause inflammation in a kitten’s intestines that leads to diarrhea and/or vomiting. Also beware that kittens are not able to digest cow milk, and even though many kittens will readily lap it up, the lactose in cow’s milk may cause diarrhea. Some kittens may also have intolerances to various ingredients. If a kitten has recurrent or ongoing diarrhea and no evidence of infection, they might have an intolerance.

Toxins

If you suspect your kitten has eaten something they shouldn’t have, have them evaluated by a veterinarian right away. Some common toxins that may cause diarrhea in kittens include cleaning agents (e.g., bleach, carpet fresheners and shampoos, dryer sheets, fabric softeners, and tablets used for toilet cleaning), rat poisons, human pain medications (ibuprofen and acetaminophen), and household plants (make sure any plants you get are not toxic to kittens).

Eating Strings and Other Things

Some kittens are drawn to strings, ribbons, rubber bands, hair ties, plastic, and other non-food items. When kittens eat indigestible items, it can irritate their stomachs and intestines and cause vomiting and/or diarrhea. In some instances, these objects can also get stuck in a kitten’s stomach or intestines, and this can lead to vomiting and/or diarrhea.

What Causes a Kitten to Have Diarrhea With Blood in It?

Some bacteria, such as salmonella, clostridium, and campylobacter, as well as some intestinal parasites like coccidia, Tritrichomonas foetus, giardia, and whipworms, may cause bright red blood in the stool.

Blood in a kitten’s poop can also be caused by damage and inflammation to the large intestine and colon as objects pass through. Bleeding in the stomach and small intestine often causes stools to look dark and tarry. Kittens that have blood in their stool are at a greater risk for developing more serious infections.

What Causes a Kitten to Vomit and Have Diarrhea?

Vomiting frequently accompanies diarrhea in kittens that are infected by a virus, bacteria, or parasite. Eating foreign objects may also cause both vomiting and diarrhea. When kittens have both, it is cause for concern, as they can quickly become dehydrated.

What Causes Yellow Diarrhea in Kittens?

Yellow diarrhea in kittens may signal some sort of bacterial imbalance in the gut, or it may also be caused by toxin exposure or liver disease. Contact your vet if you see:

Yellow diarrhea in kittens under 4 months of age
Yellow diarrhea that lasts longer than 24 hours in kittens over 4 months of age
Yellow diarrhea along with other signs of not feeling well, such as vomiting, decreased appetite, or lethargy

What Causes Soft Stool in Kittens?

Your cat’s colon absorbs water as feces pass through the digestive tract. If feces are passing through too quickly or the colon can’t effectively absorb water (possibly due to underlying inflammation in the colon), the stools may be softer than normal.

It’s normal for a kitten under stress to have a few soft stools. However, if your kitten is eating, drinking, and acting normally but has soft stools for more than a day or two, it’s a good idea to have a stool sample evaluated by a veterinarian to rule out infection.

What to Do if Your Kitten Has Diarrhea

In most cases, a single bout of diarrhea, or diarrhea with a clear cause, like stress or changing foods, is nothing to worry about. If your kitten is over 4 months of age and has a bout or two of diarrhea but no other symptoms, it may be okay to wait 24 hours to have them evaluated by their veterinarian.

However, your kitten should see a veterinarian right away if you see any of the below:

Kittens under 4 months of age experiencing any diarrhea
Kittens over 4 months of age with frequent and watery diarrhea, both vomiting and diarrhea, or other signs of not feeling well, such as decreased interest in eating or lethargy
You suspect your kitten ate something they shouldn’t have (a foreign object or a potential toxin)
There is blood in the diarrhea
Your kitten is showing signs of dehydration (e.g., tacky gums, lethargy, and decreased skin elasticity, or when you gently pull up on the skin between the shoulder blades, it does not quickly snap back into place).
Kittens over 4 months of age that have had diarrhea for more than 24 hours.

Home Remedies for Diarrhea in Kittens

If your kitten is over 4 months of age, their only symptom is diarrhea, and they are otherwise acting normally, try the following approaches to control diarrhea:

Offer a bland diet, like two parts cooked white rice mixed with one part boiled, boneless, skinless chicken breast. Typically, it is best to offer small, frequent meals when feeding a bland diet.
Add a probiotic to your kitten’s diet to promote digestive health. Nutramax Proviable and Purina FortiFlora are two good options.

How Vets Diagnose the Cause of Kitten Diarrhea

Your vet will likely do a physical examination and take a stool sample to check for intestinal parasites. Depending on these findings, your veterinarian may also recommend sending the stool sample to a lab so they can test for intestinal parasites that may not be as easily recognizable.

They may also want to run special tests to look for evidence of viral and bacterial infections and do bloodwork and take a urine sample to look for dehydration. The vet will check electrolytes, glucose levels, and protein levels. Depending on your kitten’s history, x-rays or ultrasound may be recommended to find foreign bodies. If it’s chronic or recurrent diarrhea, fecal cultures and a diet trial may be recommended.

Treating Kitten Diarrhea

Diarrhea in kittens is dangerous because it can quickly lead to dehydration. In mild cases of diarrhea where there’s no evidence of significant dehydration, your veterinarian may recommend giving your kitten an oral electrolyte solution to keep them hydrated.

If there is mild dehydration, fluids may be administered under the skin (subcutaneous fluids). In cases with moderate to severe dehydration, hospitalization with IV fluids will be required.

Some other treatments include:

Probiotics
Anti-diarrheal medications (Proviable Diarrhea Kit or Pro-Pectalin Paste)
Prescription diets (Royal Canin Gastrointestinal Kitten, Purina Pro Plan EN, or Hill’s Prescription Diet i/d)
Antibiotics may be recommended in cases of suspected bacterial or viral infection. They don’t treat viruses but may help prevent secondary bacterial infections.
Dewormers or antibiotics to kill parasites or prevent infection
Surgery, if there is a concern about an obstruction or hernia

Frequently Asked Questions

What can I feed a kitten with diarrhea?

Kittens with diarrhea may benefit from a temporary bland diet while waiting to see their veterinarian. If your kitten doesn’t seem very interested in the bland diet, another option is to feed a canned version of their current diet and add a little bit of plain, canned pumpkin.

By the time kittens are 6 weeks old, they are usually old enough to be weaned and no longer reliant on their mother’s milk. If your kitten is less than 6 weeks old or around 6 weeks old and has not been weaned, it is important to use a commercial milk replacer for kittens (like KMR). Do not offer them cow’s milk, as kittens are unable to digest the lactose in cow’s milk, and it can lead to worsening diarrhea.

What questions will my veterinarian ask?

Your vet will ask for a copy of your kitten’s vaccination records and if you know anything about their mother’s vaccination status and deworming history. They may also ask:

Where did you get your kitten?
Is your kitten on any sort of monthly flea and heartworm prevention (if they are old enough)?
How long has your kitten had diarrhea?
How are they acting at home?
Are they still eating/drinking normally?
Has there been any blood in the diarrhea?
Have there been any recent changes in their food or treats?
Have they recently gotten into anything that they shouldn’t have?