Cat Diarrhea
Diarrhea in cats can range from a short-lived stomach upset to a sign of infection, parasites, or disease elsewhere in the body. Because cats are masters at hiding illness, any visible change in stool is worth paying attention to—and this page will help you know when to monitor at home and when to call your vet.
When to Call a Vet for Cat Diarrhea
Go to the ER now
- ● Go to an emergency vet right away if your cat has black, tarry stool or large amounts of blood in the diarrhea.
- ● Seek emergency care if diarrhea happens along with repeated vomiting, collapse, severe weakness, or your cat cannot keep water down.
- ● Get urgent emergency help if your cat seems dehydrated, has pale gums, or is acting severely lethargic or unresponsive.
- ● Go now if you suspect your cat ate a toxin, poisonous plant, foreign object, or unsafe human medication.
- ● Kittens, senior cats, and cats with diabetes, kidney disease, cancer, or other chronic illness should be treated as emergencies if diarrhea is severe or frequent.
See a vet within 24 hours
- ● Call your vet the same day if diarrhea lasts longer than 24 to 48 hours.
- ● Make a prompt appointment if your cat also has poor appetite, vomiting, abdominal pain, fever, or is hiding more than usual.
- ● Contact your vet if the stool contains small streaks of blood or mucus, or if your cat is straining in the litter box.
- ● Call your vet if diarrhea keeps coming back, even if your cat seems otherwise normal.
- ● If you have more than one cat and several pets have diarrhea, call your vet promptly in case of infectious or toxic causes.
Watch at home, call if it worsens
- ● You may be able to monitor briefly at home if your adult cat has one mild episode of loose stool and is otherwise eating, drinking, and acting normally.
- ● Keep a close eye on litter box habits, stool appearance, and energy level over the next 12 to 24 hours.
- ● Monitor more carefully after a recent diet change, new treats, or a stressful event, since these can sometimes trigger short-term diarrhea.
- ● Offer fresh water and watch for any signs of dehydration or worsening symptoms.
- ● If anything seems off—or if you are unsure—call your vet, because cats often hide how sick they feel.
Common Causes of Cat Diarrhea
Diet change or food intolerance
A sudden switch in food, rich treats, or eating something unusual can upset a cat's digestive tract. Some cats also react poorly to certain ingredients or have food sensitivities.
Parasites
Intestinal parasites such as worms, coccidia, or giardia can cause loose stool, especially in kittens or cats from shelters or multi-cat homes. A fecal test is often needed to confirm the cause.
Infections
Viruses, bacteria, and protozoal infections can trigger diarrhea, sometimes with vomiting, fever, or loss of appetite. If multiple cats are affected, an infectious cause becomes more likely.
Toxins or irritants
Cats may develop diarrhea after exposure to poisonous plants, chemicals, spoiled food, or certain medications. These cases can become serious quickly and should prompt a call to your vet.
Inflammation or foreign material
Inflammatory bowel disease, irritation in the intestines, or swallowing non-food items can lead to diarrhea. Some cats may also show abdominal discomfort or changes in appetite.
Disease elsewhere in the body
Diarrhea is not always just a stomach problem. Cornell and Merck note that cats can have diarrhea with conditions such as hyperthyroidism, kidney disease, liver disease, immune problems, or cancer.
What to Do at Home
If your cat has mild diarrhea but is otherwise bright, alert, and drinking, careful home monitoring may be reasonable for a short period. Keep in mind that cats can deteriorate quietly, and over-the-counter remedies can be harmful to them, so home care should stay conservative and short-term unless your veterinarian advises otherwise.
- Make sure your cat has constant access to fresh water and watch closely for signs of dehydration.
- Do not give human anti-diarrheal medications unless your veterinarian specifically tells you to do so.
- If your veterinarian recommends diet adjustment, follow their instructions carefully and avoid sudden food changes.
- Check the stool for blood, mucus, worms, or black tarry color, and take a photo or bring a fresh sample to the appointment if you can.
- Monitor appetite, vomiting, energy level, hiding behavior, and litter box frequency—not just stool consistency.
- Call your vet sooner rather than later if your cat is a kitten, senior, or has any ongoing medical condition.
Frequently Asked Questions
Why does my cat have diarrhea but seem normal otherwise?
When should I worry about diarrhea in my cat?
Can I give my cat over-the-counter medicine for diarrhea?
What will the vet do for a cat with diarrhea?
Is diarrhea in cats ever an emergency?
Disclaimer: The information provided in this article is for educational purposes only and does not constitute veterinary medical advice. Reading this content does not establish a veterinarian-client-patient relationship. Every pet is different — always consult a licensed veterinarian before making decisions about your pet's health, diet, or care. If you'd like personalized guidance, you can talk to one of our vets. If your pet is experiencing a medical emergency, contact your local emergency animal hospital immediately.