You’ve had your cat for years. Maybe over a decade. You know their habits, the way they like their food warmed just so, and how they always nap in that same sunny spot near the window. So when something changes—especially something as uncomfortable and messy as diarrhea—it’s hard not to worry.
And rightly so. Diarrhea in senior cats isn’t always a passing issue. Sometimes it’s just a reaction to food or stress. Other times, it can be a sign of something deeper. More chronic. Possibly even serious.
Let’s take a closer look—gently, but honestly.
Is Diarrhea in Senior Cats Normal?
The short answer? Not really. Occasional soft stool might happen here and there—maybe from a dietary indiscretion or mild stress. But consistent diarrhea, especially in an older cat, is a sign that something’s off.
Senior cats, typically defined as those over 11 years old, have aging bodies that don’t process food or fight inflammation as well as they used to. According to the American Association of Feline Practitioners (AAFP), many diseases become more common in older cats—including gastrointestinal disorders.
So no, chronic diarrhea isn’t normal. It’s not something to just clean up and forget. It’s your cat’s body telling you something.
Common Causes of Diarrhea in Senior Cats
The tricky part is that diarrhea isn’t a disease—it’s a symptom. And it can have many possible causes, some simple, others more complicated.
1. Dietary Changes or Sensitivities
Even a small change in your cat’s food can cause digestive upset. As cats age, their tolerance for certain ingredients—grains, dairy, even proteins—may shift.
Older cats may also develop food intolerances. You might’ve fed them the same brand of kibble for years, but suddenly, it doesn’t sit well anymore.
Sometimes it’s not even what they eat, but how much. Or how fast. Or how long it sat in the bowl.
2. Inflammatory Bowel Disease (IBD)
IBD is one of the most common causes of chronic diarrhea in senior cats. It’s not fully understood, but it involves inflammation of the intestinal lining, which disrupts nutrient absorption and digestion.
According to a review published in Veterinary Sciences, IBD can cause vomiting, diarrhea, weight loss, and even changes in appetite. And it can mimic other diseases, which makes diagnosis tricky (Cerquetella et al., 2020).
Some cats with IBD improve with diet changes. Others need immunosuppressive drugs like corticosteroids. It really depends.
3. Hyperthyroidism
If your older cat has diarrhea and is also losing weight despite a good appetite—or is drinking and peeing more than usual—hyperthyroidism could be the culprit.
This overactive thyroid condition is surprisingly common in senior cats. One study published in the Journal of Feline Medicine and Surgery estimated its prevalence at 10% among cats over 10 years old (Peterson et al., 2007).
Diarrhea in this case often comes with increased activity, restlessness, and sometimes vomiting.
4. Chronic Kidney Disease (CKD)
While CKD typically causes increased thirst and urination, it can sometimes lead to gastrointestinal issues like nausea, vomiting, or even loose stool. If your cat’s kidneys aren’t filtering toxins effectively, it can throw the whole system off.
5. Cancer
Unfortunately, gastrointestinal tumors (like lymphoma) are more common in senior cats. Diarrhea that doesn’t improve—or gets worse despite treatment—could signal something more serious.
6. Parasites and Infections
You’d think an indoor senior cat wouldn’t get parasites. But it happens. Giardia, coccidia, or even bacterial infections like Clostridium perfringens can sneak in, especially if there’s exposure to contaminated water or another pet.
Some of these can be diagnosed through fecal testing, though intermittent shedding makes them frustrating to catch.
What It Might Look Like (and Why It Matters)
Diarrhea isn’t always… well, the same.
It might be watery. Mucousy. Yellowish. Bloody. Black and tarry. Each of those presentations tells your vet something different.
- Bloody stool (bright red) might suggest inflammation in the lower intestine.
- Black stool could mean bleeding higher up in the GI tract.
- Greasy stool might hint at pancreatic insufficiency.
Gross? Yes. But weirdly fascinating. And important.
When to See a Vet
Here’s a quick rule of thumb, if your senior cat has diarrhea for more than 48 hours, or if it’s accompanied by other symptoms like:
- Weight loss
- Vomiting
- Lethargy
- Dehydration
- Blood in stool
- Loss of appetite
…it’s time for a vet visit.
Cats dehydrate easily—especially seniors. Diarrhea can tip the balance quickly.
Your vet may run bloodwork, fecal tests, or even imaging like an ultrasound. In some cases, they might recommend a biopsy to confirm IBD or rule out cancer.
Treatment Options
Treatment depends entirely on the cause. There’s no one-size-fits-all approach.
Here’s what might be involved:
- Dietary Management: Switching to a novel protein diet, hydrolyzed food, or a highly digestible prescription formula.
- Probiotics: Supplements like FortiFlora or Proviable are often recommended to restore gut balance.
- Medications: Anti-inflammatory drugs (like prednisolone), antibiotics, anti-parasitics, or antidiarrheals depending on the underlying issue.
- Fluid Therapy: Especially if dehydration is a concern.
And sometimes… the cause remains elusive. In these cases, vets might try a trial-and-error approach, starting with diet and adjusting as needed.
What You Can Do at Home
- Monitor everything: Keep track of stool consistency, frequency, appetite, and behavior. A simple diary helps.
- Hydration is key: Add water to food or offer unsalted broth if your cat’s not drinking.
- Avoid over-the-counter meds: Never give Imodium or Pepto-Bismol unless your vet says it’s safe.
- Consider litter box placement: Older cats might struggle to get to the box if it’s far or has high sides. Accidents might not always be diarrhea-related.
Final Thoughts: It’s Not “Just” Diarrhea
Diarrhea in senior cats is more than just a mess in the litter box. It’s often a sign that the body isn’t working quite right—and at this age, that deserves attention.
Maybe it’s something simple. Maybe not. Either way, early care and observation make a difference.
After all, our cats spend their lives trusting us. The least we can do is listen when their bodies try to speak.
References:
- Cerquetella, M., Spaterna, A., Laus, F., Tesei, B., Rossi, G., Antonelli, E., & Villanacci, V. (2020). Inflammatory bowel disease in the dog: differences and similarities with humans. Veterinary Sciences, 7(1), 11. https://doi.org/10.3390/vetsci7010011
- Peterson, M. E., & Ward, C. R. (2007). Etiopathologic findings of hyperthyroidism in cats. Journal of Feline Medicine and Surgery, 9(5), 314-326. https://doi.org/10.1016/j.jfms.2007.02.006
- American Association of Feline Practitioners. (2021). Senior Cat Care Guidelines. https://catvets.com
