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Causes and treatment of diarrhea in cats
Last reviewed: 08.07.2025
Diarrhea is characterized by frequent loose stools. It can be caused by something as simple as a change in diet, or by a more serious illness or infection. Diarrhea can start suddenly and last only a short time. It can also last for weeks or months, or come and go. A single bout of diarrhea in a cat is usually nothing to worry about, but if it continues for more than a day or two, dehydration can occur.
What causes diarrhea?
- Change in diet
- Intolerance to dairy or other products
- Consumption of spoiled food
- Hairballs in the stomach
- Allergic reaction
- Bacterial or viral infection
- Internal parasites such as roundworms, coccidia and giardia
- Inflammatory bowel disease
- Kidney or liver disease
- Cancer or other tumors of the gastrointestinal tract
- Certain medications
- Hyperthyroidism
- Colitis
What are the main symptoms of diarrhea?
Frequent loose stools are the most common symptom of diarrhea. Other signs include flatulence, blood in the stool, and an urge to defecate. Drowsiness, dehydration, fever, vomiting, loss of appetite, weight loss, and an increased urge to defecate may also accompany diarrhea.
If your cat's diarrhea is accompanied by black or bloody stool, she may have internal bleeding in the stomach or small intestine and should be seen by a veterinarian immediately.
How to treat diarrhea?
It is often recommended that you withhold food for 12 to 24 hours while your cat is suffering from diarrhea, but provide plenty of fresh, clean water to prevent dehydration. Consult your veterinarian regarding the proper course of treatment for your cat.
When is it necessary to show a cat to a veterinarian?
Take your cat to the veterinarian if diarrhea continues for more than a day, or if you observe lethargy, vomiting, fever, dark or bloody stools, an urge to defecate, decreased appetite, or unexplained weight loss.
What to expect at the vet's office?
The veterinarian will examine the animal for underlying medical conditions and may also take a stool sample to check for internal parasites and perform blood tests to determine the possible cause of the diarrhea.
Other diagnostic tests may include x-rays, ultrasound, cultures, endoscopy, and biopsy. The diagnostic tests performed and the recommended treatment will depend on how long the diarrhea has been going on and the severity of your pet's condition.
Are certain cats prone to diarrhea?
Long-haired cats that frequently develop hairballs may experience occasional bouts of diarrhea. Additionally, cats that spend a lot of time outdoors may be at increased risk of internal parasites or consuming inappropriate foods, which can cause diarrhea.
How to prevent diarrhea?
Try to avoid giving your cat dairy products, no matter how much she loves them! Almost all cats enjoy the taste of milk and yogurt, but some adult cats lack lactase, an enzyme needed to digest dairy products. Undigested lactose ends up in the large intestine, where it ferments and can cause gas and diarrhea.
Also, if you decide to change your cat's food, it is a good idea to introduce it gradually, mixing it with the old brand of food to ensure an easier transition for your pet's gastrointestinal tract.