Cat symptom
Diarrhea in cats
Reviewed by the Webvet Veterinarian Team · Last reviewed June 22, 2026
Loose or watery stool. Mild diarrhea in an otherwise bright adult pet is often short-lived, but persistent, bloody, black, or diarrhea with vomiting or weakness can cause dehydration and needs veterinary care.
Common causes of diarrhea in cats
- Diet change, scavenging, or food intolerance
- Intestinal parasites (worms, giardia)
- Stress or anxiety
- Viral or bacterial infection
- Chronic conditions (inflammatory bowel disease, pancreatitis)
Who's most at risk
- Diet changes, scavenging, or rich treats
- Puppies and kittens
- High-stress events — travel, boarding, a new home
- Pets overdue for parasite prevention
What you can do at home
- Offer plenty of fresh water to prevent dehydration
- For a bright adult pet with mild diarrhea, feed small portions of a bland, easily digestible diet for a day or two
- Collect a fresh stool sample to bring to your vet if it continues
When to see a vet
- Blood or black, tarry stool
- Diarrhea lasting more than 48 hours, or in a puppy/kitten
- Also vomiting, weak, not eating, painful, or showing signs of dehydration
When it's more serious
- Young or weak pets can crash fast (including parvovirus) — seek care now.
- Blood or black, tarry stool can mean GI bleeding or infection — get them seen today.
- Diarrhea plus vomiting dehydrates pets quickly — see a vet today.
- Diarrhea beyond two days warrants a vet visit and likely a stool test.
What your vet may do
- Exam and a dehydration check
- Fecal test for parasites and infection
- Bland or prescription diet, probiotics, and a dewormer if indicated
- Bloodwork or imaging if it's persistent or severe
Questions to ask your vet
- Should we test a stool sample?
- Is my pet dehydrated?
- What should I feed to settle the gut?
- When should ongoing diarrhea worry me?
Frequently asked questions
What causes diarrhea in cats?
Loose or watery stool. Mild diarrhea in an otherwise bright adult pet is often short-lived, but persistent, bloody, black, or diarrhea with vomiting or weakness can cause dehydration and needs veterinary care. Common causes include: Diet change, scavenging, or food intolerance; Intestinal parasites (worms, giardia); Stress or anxiety; Viral or bacterial infection; Chronic conditions (inflammatory bowel disease, pancreatitis).
Is diarrhea in cats an emergency?
Book a veterinary visit soon. See a vet right away if: Blood or black, tarry stool; Diarrhea lasting more than 48 hours, or in a puppy/kitten; Also vomiting, weak, not eating, painful, or showing signs of dehydration.
What can I do at home for a cat with diarrhea?
Offer plenty of fresh water to prevent dehydration. For a bright adult pet with mild diarrhea, feed small portions of a bland, easily digestible diet for a day or two. Collect a fresh stool sample to bring to your vet if it continues.
A closer look at diarrhea in cats
Most diarrhea in cats is the gut's fast reaction to something it did not like, and in a bright, playful adult cat a single loose day often settles on its own within 24 to 48 hours. The single most important thing to watch is not the mess in the litter box but the cat attached to it: a cat who is still eating, drinking, and moving normally is usually in a very different situation from one who is flat, hiding, vomiting, or passing blood. That difference is what tells you whether to wait a day and watch or call your veterinarian now.
- 1Mild, one-off diarrhea in an otherwise happy adult cat is common and often short-lived.
- 2Diet changes, scavenging, intestinal parasites like giardia, stress, and infections are the usual triggers.
- 3Watch the whole cat, not just the stool: appetite, energy, and hydration matter more than a single soft poop.
- 4Blood, black tarry stool, vomiting, weakness, or a kitten with diarrhea all mean call the vet promptly.
- 5Never reach for human anti-diarrheal or pain medicines, many are toxic to cats.
A probiotic and prebiotic blend for dogs and cats that supports a steadier gut during recovery.
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What is actually happening in your cat's gut
Diarrhea is not a disease on its own, it is a symptom. Under normal conditions your cat's intestines pull most of the water back out of digested food before it becomes stool. When the intestinal lining is irritated, inflamed, or moving too quickly, that reabsorption fails and water stays in the stool, so it comes out loose or watery. The lining can be irritated by a new food, a swallowed parasite, a virus or bacteria, or the ripple effects of stress, and the gut responds the only way it knows how, by flushing the contents through faster.
Where the trouble sits also changes what you see. Diarrhea from the small intestine tends to come in larger volumes a few times a day, sometimes with weight loss over time. Diarrhea from the large intestine, or colitis, often looks like frequent small squirts, straining, urgency, and streaks of fresh red blood or jelly-like mucus on top. Neither pattern tells you the exact cause by itself, but describing it to your vet, along with the color and how often it is happening, genuinely helps them narrow things down before your cat is even on the exam table.
Why even indoor cats get diarrhea
A question owners ask constantly is how an indoor-only cat, who never hunts and never meets other animals, ends up with parasites or an infection. The truth is that indoor cats are not sealed off from the outside world. Giardia and other single-celled parasites travel on shoes, on potting soil, in shared water, and on a new kitten brought into the home. Roundworms and hookworms can arrive the same way or be carried from kittenhood. This is exactly why a fresh stool sample is such a useful thing to bring to your vet, because these organisms are often invisible until they are found under a microscope.
Diet is the other everyday culprit. Cats have famously sensitive stomachs, and switching food abruptly, offering a rich new treat, or letting them raid a countertop can all set off loose stool within a day. A genuine food intolerance or allergy can do the same thing more slowly and repeatedly. Stress deserves its own mention, because cats are quietly sensitive creatures: a house move, a new baby, a visitor, boarding, or even rearranged furniture can trigger stress colitis. And in older cats, chronic conditions such as inflammatory bowel disease, pancreatitis, hyperthyroidism, and kidney disease can all announce themselves partly through ongoing soft stool.
| Likely cause | Other signs you might notice | How urgent |
|---|---|---|
| Diet change or scavenging | Otherwise bright, normal appetite, one or two loose days | Watch at home 24 to 48 hours |
| Intestinal parasites or giardia | Soft stool that keeps returning, sometimes mucus, dull coat | Routine vet visit with a stool sample |
| Stress or anxiety | Recent change at home, otherwise well | Watch, reduce stressors, vet if it persists |
| Infection or serious illness | Vomiting, not eating, weakness, blood, black tarry stool | Same-day veterinary care |
| Kitten with diarrhea | Any diarrhea, especially with lethargy | Contact your vet promptly, kittens dehydrate fast |
How your vet pinpoints the cause
Vets tend to think in layers, starting simple and only reaching for bigger tests when the picture calls for it. The visit usually begins with your story and a physical exam, feeling the belly for pain, thickened loops, or gas, and checking hydration by the feel of the gums and the skin over the shoulders. A fecal test for worms and giardia is often the first real diagnostic, because parasites are common, treatable, and easy to miss without a microscope. That single, low-cost step resolves a surprising share of cases.
When diarrhea is persistent, severe, or paired with weight loss, vomiting, or a poor appetite, the workup widens. Bloodwork can reveal dehydration, infection, pancreatitis, thyroid disease, or kidney trouble, and imaging such as X-rays or ultrasound can rule out a blockage or show a thickened intestinal wall. For chronic cases that do not respond to diet and deworming, your vet may discuss a food trial, gut biopsies, or referral. The goal at each stage is to match the depth of testing to how sick the cat actually is, not to run every test at once.
Helping your cat at home, safely
For a bright, well-hydrated adult cat with mild diarrhea and no other worrying signs, gentle home support for a day or two is reasonable. Keep fresh water available at all times, because the biggest short-term risk of diarrhea is fluid loss. Many vets suggest a small amount of a bland, easily digestible diet, whether a veterinary intestinal food or a simple recipe like plain boiled chicken and a little white rice, fed in small, frequent portions rather than one large meal. A cat-specific probiotic and a spoonful of plain canned pumpkin can help firm things up, but these support the gut, they do not replace a vet visit when one is needed.
The probiotic vets most often send cats home with. A daily sachet stirred into wet food supports firmer stools while the gut settles.
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Give it a clear time limit. If mild diarrhea has not improved within about 48 hours, or your cat starts refusing food, hiding, or seems less bright, that is your cue to stop watching and call. Cats mask illness by instinct, so a cat who has simply gone quiet may be telling you more than the litter box is. It is always safer to check in a day early than a day late.
When cat diarrhea becomes an emergency
Some situations should not wait. Call your veterinarian, or an emergency clinic after hours, if your cat has blood in the stool or passes black, tarry stool, if diarrhea lasts more than 48 hours, or if it comes with repeated vomiting, a refusal to eat, weakness, or collapse. Kittens, senior cats, and cats with existing health conditions have far less reserve and can slide into dangerous dehydration quickly, so their threshold for a call is much lower. When in doubt, a phone call to your clinic costs nothing and often saves you a frightening middle-of-the-night scramble.
Lowering the risk of future flare-ups
Plain canned pumpkin with nothing added. A spoonful of gentle fibre is a standard first step for a cat with loose stools.
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You cannot prevent every loose day, but a few habits stack the odds in your cat's favor. Change foods gradually over five to seven days, mixing more of the new food in each day, so the gut has time to adjust. Keep treats and table scraps modest, and store trash and human food where a determined cat cannot reach it. Staying current on routine parasite prevention and deworming closes off one of the most common and preventable causes, even for indoor cats.
Managing stress matters more than most owners expect. Keep feeding times, litter boxes, and daily routines predictable, provide quiet retreats and vertical space, and introduce new pets, people, or environments slowly. For a cat with a truly sensitive stomach or a diagnosed chronic condition, your vet can help you land on a consistent diet that keeps stool firm long term. The reassuring bottom line is that most cat diarrhea is short-lived and manageable, and the cases that are not almost always show themselves through the rest of the cat, which is exactly why watching the whole animal, and trusting your vet when something feels off, is the most reliable tool you have.
For chronic or recurring diarrhea, a mail-in microbiome test gives you and your vet real data about the gut.
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Reviewed by the Webvet Veterinarian Team
This guide is general information, not a diagnosis, and does not replace an exam by your veterinarian. If your pet is in distress, contact your vet or an emergency clinic right away.