Cat Diarrhea

"Cat diarrhea has many causes. Diagnosis is based on the consistency and smell of your cat's stool and a cat's overall physical condition. The problem can be treated at home if it stops within 24 hours and the diarrhea contains no blood and is not too watery. After 24 hours cat's risk dehydration and need to be taken to a veterinarian. Better to treat a mild form of feline diarrhea than risk having the condition and dehydration worsen."

Normal cat stools that do not contain mucus, blood or undigested food. The first step to control feline diarrhea is to understand the cause. Diarrhea problems are present when your cat passes a liquid stool or a loose stool more often than is normal for your pet. If diarrhea lasts more than 24 hours you must see a veterinarian since your cat would be in danger of suffering from dehydration.

Not all diarrhea is the same with differences in color, consistency (eg; how watery) and smell being associated with specific causes. This is why whenever my cat has diarrhea, I put some in a container in case I need to bring her to the vet (which my vet actually appreciates in an odd sort of way). Often by straining the diarrhea she can see what my cat ate to cause the problem or she can spot other digestion problems such as parasites.

Your vet will ask two questions upon your arrival in their office: 1. Did the diarrhea just start? and 2. Was there a change in diet or surroundings?

Common Causes of Cat Diarrhea:

There are many causes of feline diarrhea.  These include:

Eating What They Shouldn't: Don't we all. Okay, in the case of my cat, it's amazing what goes into her mouth. This is the most common cause of diarrhea. If this is the case, the diarrhea should pass in a day or so.

Eating too much: (they say a cat reflects the habits of its owner, in this case definitely true). This can even happen when you feed your cat 1 time a day. Since they know they are only going to be fed once, they tend to over eat. A better suggestion would be several small feedings throughout the day (its how I started losing weight) or leave the food out all day and let your cat eat at her leisure (where leisure is definitely no problem for the feline queen of our house). Over eating overloads the spleen causing the diarrhea.

Cheap Pet Food:  OK, pet food is expensive. Do for your cat as you do for yourself. When I buy cheap food, I feel it in my stomach (think fast food). Same is true for your cat. In fact, you'd be surprised what they mix into a cheap bag of food. Buy a reputable brand of food that was recommended by your local pet store or vet.  At a minimum, make sure the food you buy is AAFCO certified.

Foods that your cat likes, but don't like your cat:  As I get older I can't eat pizza without a side of Tums. Same for your cat. If something new was introduced into their diet, try cutting it back out. Other foods such as those that are rich, gravies, salts, spices and fats can all cause the problem. Some cats are lactose intolerant and react to milk products with a case of diarrhea. Foods that can trigger diarrhea include beef, chicken, pork, horse meat, eggs, fish, spices, soy, corn and wheat.

Stress: Not that my cat has anything to worry about, but they do. Someone new in the house?, Moved? All are causes of stress and all cause diarrhea. Remove the causes and you will control cat diarrhea. If you can’t remove the causes, the diarrhea should pass in a couple of days as your cat adjusts to the new situation. If not, a trip to the vet is in order.

Foreign Objects: If your cat eats something like a bone, it could get caught in the intestines causing diarrhea and sometimes vomiting. Other objects like sticks, cloth, grass, paper and plastic can also cause diarrhea.

Irritating Substances: Anything that irritates the intestinal tract speeds up bowel movements preventing them from moving from a liquid to solid form. These substances include toxins (insecticides, building materials, plants, cleaning fluids) and other items such as dead animals and garbage.

Illness Related Causes of Cat Diarrhea

Diarrhea is often due to a disease in your pet's large or small intestine, or a problem with the intestinal tract. The choice of cat medicine for diarrhea will vary based on which one it is.

Small Intestine Cat Diarrhea Symptoms: Diarrhea caused by disease that resides in the small intestine is associated with a large stool with increases in number of bowel movements from 3 to 5 times a day. The cat does not have difficulty with bowel movements. This is often accompanied by vomiting, weight loss, gas and black looking blood.

Large Intestine Cat Diarrhea Symptoms: Bowel movements tend to be smaller and occur 5 or more times every day. Bowel movements are difficult. If there is blood it is usually red. Other symptoms such as vomiting or weight loss are not usually associated with large intestine cat diarrhea.

Viruses and Bacteria: Many feline viruses and bacteria will trigger cat diarrhea. Viruses include panleukopenia (feline distemper) and feline leukemia virus. Bacterial causes include clostridia, salmonella and campylobacter.

Worms: Cats may get tape worms that in turn cause diarrhea. To control cat diarrhea you need to eliminate the worms.

Allergies and Pesticides: If your cat is allergic or has been exposed to pesticide, it could trigger diarrhea. It is thought that irritable bowel disease (IBD) is caused by an allergic reaction. To control cat diarrhea in this case you need to eliminate single foods until the diarrhea ends.

Cat Tumor and Diarrhea: If you see diarrhea in an older cat, the cause could be a tumor. Tumors can occur in the glands (adenocarcinoma) or in several places along the intestine (lymphosarcoma).

Fungus: Certain areas of the United States have a fungus that could cause the diarrhea.

Medicines: Certain medications could be the cause. Check the labels of any prescription medications your cat might be taking and check with your vet.

Examination of the feline diarrhea can be helpful in understand its'  cause such as the cat diarrhea color of stool.  Here is a list of common signs.

Diagnosis of Cat Diarrhea Based on Color, Texture and

Diarrhea Sign

Possible Cause Of Cat Diarrhea


Indicates the stool moved quickly through the digestive system.

Black and Tarry

From upper bleeding in the upper intestine tract


Lower bowel or colon bleeding

Pasty and Light in color:

Liver disease

Large, gray and smells bad

Digestion problem

Soft and bulky

Over feeding or low quality food


Bowel wall problem such as enteritis


Bacterial infection

Greasy stool

Mal absorption syndrome

Sour milk odor

From over feeding

Awful Smell

Internal infection (feline panleukopenia)

Several bowel movements in an hour


3 to 4 large movements

Mal absorption syndrome or IDB: irritable bowel disease

Treatment of Cat Diarrhea:

It is important to understand the cause of diarrhea and then stop the feline diarrhea. Feline nutrition is important when treating diarrhea.If the diarrhea lasted less then 24 hours, then do not feed for 24 hours. Provide small amounts of water to help with hydration. As your cat gets better provide 3 or 4 small meals a day with a food that is high in fat and poultry protein (Purina Tender Vittles or Hills prescription diet feline c/d).  See our guide to household cures for feline diarrhea for more information.

If the diarrhea lasts for more than 24 hours than you must see your veterinarian for treatment. There are many diarrhea medicines to choose from.

If diarrhea is a common problem for your cat, consider an herbal supplement such as RunnyPoo which despite its silly name contains natural ingredients such as plantain that are known to help firm up bowel movements and improve digestive health. You should see improvement after several days. See a veterinarian if you do not see some improvement.


Small Intestinal Diarrhea; Gaschen, Frederic DMV

Cat Owner's Home Veterinary HandbookDelbert G. Carlson, DVM and James M.Giffin, MD


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