It’s not the most fun topic to read about, but if you’re a cat parent, you’ve likely dealt with an unexpected mess in the litter box at some point. Diarrhea in cats can range from a one-time incident to a recurring issue that signals something more serious. Let’s walk through what you need to know about cat diarrhea, from common culprits to treatment options and when to call your veterinarian.
Common Causes of Cat Diarrhea
Diarrhea in cats isn’t a diagnosis—it’s a symptom. The key to treating it effectively is figuring out the underlying cause. Here are some of the most common reasons healthy adult cats might experience an upset gastrointestinal tract.
Dietary Changes or Food Allergies
A sudden change in your cat’s diet—like switching to a new brand of food or giving them table scraps—can trigger acute diarrhea. Cats tend to have sensitive digestive systems, and it’s best to transition to a new food gradually over 7–10 days.
Food allergies can also be the culprit. If your cat consistently has loose stools or other signs like itching, hair loss, or vomiting, an elimination diet trial might help identify the offending ingredient.
In some cases, your cat may have food intolerances rather than true allergies, meaning their digestive system struggles to break down certain ingredients, leading to gastrointestinal upset.
Inflammatory Bowel Disease (IBD)
IBD is a common cause of chronic diarrhea in cats, especially middle-aged and older felines. IBD happens when the intestinal lining becomes inflamed, making it harder for your cat to absorb nutrients. This condition often presents with diarrhea, vomiting, weight loss, and abdominal pain.
Diagnosing IBD usually involves a combination of bloodwork, stool tests, imaging, and sometimes intestinal biopsies.
Intestinal Parasites
Parasites like roundworms, hookworms, and Giardia can cause diarrhea in cats, especially in kittens or cats that spend time outdoors. These microscopic invaders irritate the intestinal lining and often lead to severe diarrhea with mucus or even blood. Preventive care such as routine deworming and fecal testing are key to keeping your cat parasite-free.
Infections
In some cases, a viral infection such as feline panleukopenia (also known as feline distemper) may be responsible for diarrhea, especially in unvaccinated cats or kittens in shelters.
What About Chronic Diarrhea in Cats?
If your cat has diarrhea that persists for more than a few days, or if it’s an ongoing issue that comes and goes, that’s considered chronic diarrhea. In these cases, the cause is often more complex than a one-off tummy upset, and further tests may be needed to diagnose the underlying cause.
Potential culprits include:
- Inflammatory bowel disease
- Food allergies or intolerances
- Liver disease
- Pancreatic insufficiency
- Feline distemper (especially in unvaccinated kittens)
Chronic diarrhea can lead to dehydration, nutrient deficiencies, and weight loss. It’s important not to ignore it—healthy cats should not have regular diarrhea.
What Pet Parents Can Do
If your cat has acute diarrhea but is still eating, drinking, and behaving normally, there’s a good chance the issue is temporary. Just like humans, cats can have an occasional stomach upset that clears up on its own. That said, it’s still important to take action early to prevent dehydration and monitor for signs that something more serious might be going on.
Here are a few things you can do at home to support your cat’s recovery.
1. Offer a Bland Diet
Sometimes, giving your cat’s gastrointestinal tract a break is the best thing you can do. A short-term bland diet can help soothe irritation and firm up loose stools.
- Stick to easy-to-digest foods like boiled chicken (no seasoning, skin, or bones) and plain white rice.
- Feed small portions several times a day rather than one or two large meals.
- If you’re not sure what to feed, give us a call and we can recommend a prescription gastrointestinal diet designed specifically for feline diarrhea.
Avoid rich, fatty, or new foods during this time—even treats. And always transition back to your cat’s regular food slowly over several days.
2. Keep Your Cat Hydrated
Diarrhea in cats can quickly lead to dehydration, especially in kittens or smaller cats. Make sure clean, fresh water is always available.
- If your cat isn’t drinking much, try offering water in a shallow dish or pet fountain—some cats prefer moving water.
- You can also add a little water or unseasoned bone broth (low sodium) to their food to encourage more fluid intake.
- In mild cases, wet food can also help with hydration.
If your cat shows signs of severe diarrhea or becomes lethargic or weak, fluids may be needed under the skin or intravenously.
3. Monitor the Litter Box Closely
Yes, it’s not the most glamorous job, but your cat’s litter box is full of important clues.
Watch for these subtle signs that something may be off:
- The consistency of the stool (watery, mushy, formed but soft)
- Increased frequency—going more often than usual can signal irritation
- Other symptoms like blood, mucus, or strong odor
- Straining, which could indicate discomfort or abdominal pain
Take note if your cat is passing watery stools, or if you see fresh blood, mucus, or a particularly foul odor—these are clues that something more serious may be going on.
Tracking these details can help us diagnose the underlying cause more accurately if the diarrhea persists or becomes chronic.
4. Avoid Over-the-Counter Human Medications
This is an important one: Do not give your cat human anti-diarrhea meds like Pepto-Bismol, Imodium, or aspirin. Many of these are toxic to cats, and even small amounts can lead to serious side effects or poisoning.
If you feel your cat needs something beyond supportive care, always give us a call first.
When to Seek Veterinary Care
While some cases of cat diarrhea resolve on their own, others can signal a more serious issue that requires medical attention. If your cat is showing other symptoms or if the diarrhea doesn’t improve quickly, don’t wait—contact a veterinarian immediately.
Call your vet if:
- The diarrhea persists for more than 48 hours
- You see blood in the stool
- Your cat is vomiting, lethargic, or refusing to eat
- There’s evidence of abdominal pain (such as vocalizing, hiding, or hunching over)
- You suspect exposure to intestinal parasites, a new medication, or household toxins
- Your cat is very young, very old, or has an existing condition like liver disease
Young kittens, in particular, are at an increased risk for complications due to their small size and immature immune systems. Even one day of watery diarrhea in a kitten can lead to dangerous dehydration or nutrient loss. Senior cats and cats with chronic illnesses also have less ability to bounce back from GI upset.
What to Expect
When you bring your cat in, we’ll start with a thorough physical exam and ask about your cat’s diet, behavior, and any clinical signs you’ve noticed. To get to the underlying cause, we may recommend diagnostic tests such as:
- Blood work to evaluate organ function, hydration status, and signs of infection or inflammation
- A fecal exam to check for intestinal parasites or harmful bacteria
- Abdominal ultrasound or X-rays to assess the GI tract for blockages, inflammation, or structural issues
- Additional testing if conditions like IBD or liver disease are suspected
Quick intervention is key to keeping your cat comfortable and preventing more serious health problems. If you’re ever in doubt, it’s always better to err on the side of caution and have your cat checked out.
At Modern Vet, we’re here to provide compassionate, expert care—because no one knows your cat like you do, and no one treats them like we do.
Treat Cat Diarrhea and Other Digestive Issues at Modern Vet
There are many reasons your cat might be experiencing GI upset. Some cases resolve quickly, but others point to an underlying cause that needs medical care. Some common signs that it’s time to schedule a visit include persistent cat diarrhea, vomiting, loss of appetite, or unusual lethargy.
The good news? With the right diagnosis and treatment plan, most cats recover fully.
If your cat is having ongoing digestive issues or if you’re unsure what’s causing the litter box trouble, our team at Modern Vet is here to help. We offer compassionate, expert care to get your furry friend feeling like themselves again.
