Cat Diarrhoea Explained: Common Symptoms, Causes, and Effective Treatments

Watching your cat struggle with loose, watery stool is never easy. While the occasional soft stool can sometimes happen without serious cause, persistent or repeated diarrhoea often signals that something in your cat’s health or environment needs closer attention. 

As a cat parent, you may feel anxious about what’s “normal” and “what’s not”, especially when your feline friend seems otherwise fine. This blog will walk you through how to recognise diarrhoea, explore the causes (from the harmless to the serious), and learn what you can do at home, and clearly identify when it's time to seek veterinary help. 

What Does Diarrhoea Look Like?

Diarrhoea in cats is more than just “a bit runny stool”. It involves changes in stool consistency, frequency, and appearance. A few signs to look out for include:

• Frequent trips to the litter box, often with loose, watery, or semi-formed stools. 

• Abnormal stool colour such as yellow, green or dark tar-like (which may hint at digestion or bleeding issues). 

• Mucus coating the stool, sudden urgency, or a complete lack of stool output for hours after frequent attempts. 

• Accompanying signs such as vomiting, a sharp drop in appetite, lethargy, dehydration (sticky gums, sunken eyes) or weight loss. 

Acute vs. Chronic: What’s the Difference?

Understanding whether your cat’s diarrhoea is short-term (acute) or long-term (chronic) is key:

• Acute diarrhoea starts suddenly and usually lasts less than 14 days. These cases often stem from dietary mishaps or minor infections.

• Chronic diarrhoea persists for weeks or repeatedly returns. It often correlates with more complex health issues, like inflammatory disease or organ dysfunction.

Common Causes of Cat Diarrhoea

Cat diarrhoea is usually a sign that something is upsetting your feline’s digestive system. It could be anything from a sudden food change or spoiled meal to parasites, infections, or food intolerances. Understanding what’s causing it is the first step to helping your cat feel better.

• Dietary Triggers and Gut Upsets

Often the simplest causes are overlooked: food changes, over-eating, eating too fast or feeding table scraps. These habits can stress the gut and leading to loose stools.

• Infections, Parasites and Toxins

Intestinal parasites (worms, Giardia), viral or bacterial infections, ingesting toxins or foreign objects can all trigger heavy or recurring diarrhoea. These causes tend to affect kittens or outdoor cats more often.

• Food Intolerances, Allergies & GI Inflammation

When cats react badly to certain proteins or ingredients, the digestive tract may become inflamed - leading to persistent or recurring diarrhoea.

• Metabolic, Organ & System-Wide Disorders

Diarrhoea can be the tip of the iceberg. Conditions like kidney or liver disease, hyperthyroidism, intestinal tumours, or inflammatory bowel disease (IBD) may all present with loose stools among other signs.

• Stress, Environment & Lifestyle Changes

A shift in routine, such as a new pet, relocating home, or even a new feeding spot  can upset your cat’s digestive balance and trigger diarrhoea simply because of stress.

What You Can Safely Do at Home

Here are some things that you can do at home:

1. Monitoring & Documenting Your Cat’s Condition

Start by observing your cat’s behaviour and stool closely. Note how many times your cat uses the litter box, what the stool looks like, whether your cat is eating and drinking as usual, and any changes in environment, diet or recent medication. These details are incredibly useful if you need to visit a vet.

2. Diet & mealtime adjustments

• Transition any new food gradually over 7-10 days to reduce digestive shock.

• If diarrhoea begins, temporarily shift to a simpler, highly digestible diet (often low fat, moderate fibre) until symptoms calm.

• Avoid table scraps, sudden treats or human food during recovery.
  

3. Hydration, Probiotics & Gut Support

Diarrhoea can quickly lead to dehydration. Ensure your cat always has fresh water. Consider adding a pet-safe broth or wet food to support hydration. Probiotics may assist in restoring healthy gut flora, but only use ones approved for cats and ideally under veterinary recommendation. 

4. Removing Hazards and Stabilising Routines

Secure household items that a curious cat might ingest (cables, small toys, plants), reduce sudden feed changes, minimise stress in the environment and keep litter box access easy. These steps reduce further gut triggers.

When It’s Time to Visit the Vet

If home care isn’t enough or your cat shows concerning signs, professional care is necessary.

Urgent signs include:

• Diarrhoea lasting more than 24 to 48 hours, especially if accompanied by vomiting. 

• Blood in stool (bright red or dark tar-colored), severe lethargy, refusal to eat or drink, dehydration or abdominal pain.

• Very young kittens, senior cats, or cats with known health issues developing diarrhoea.

What to Expect at the Vet:

Your vet may ask for a stool sample, run blood tests, imaging or even biopsy in complex cases. The goal: identify the root cause, not just treat the mess.

Preventing Recurrence & Long-Term Management

Once your cat’s tummy has settled, the next step is preventing it from happening again. Long-term management focuses on identifying triggers, maintaining a consistent diet, and making small lifestyle adjustments to keep their digestive health on track. Here are some things that you can follow:

• Maintain a consistent, high-quality diet suited to your cat’s life stage and health status.

• Introduce diet changes slowly, over several days.

• Stay on top of de-worming, vaccinations and parasite prevention.

• Provide mental stimulation and minimise stress.

• Choose foods designed for sensitive digestion if your cat has known GI history.

Cat diarrhoea is more than just a one-off tummy issue, but a way of signalling that something isn’t quite right. Occasional loose stools may settle on their own, but if your cat’s diarrhoea keeps coming back, it could point to food sensitivities, stress, or an underlying gut imbalance that needs attention.

At Heads Up For Tails, we focus on nutrition that truly supports feline health. Our Meowsi cat food range has real meat, quail eggs, veggies, and are easy-to-digest  meals that nourish the gut and keep your cat comfortable.

Explore our collection to find meals that help your feline feel better from the inside out!

Frequently Asked Questions

Will yogurt help settle my cat’s stomach?

No. Cats don’t digest dairy well; yogurt may actually worsen diarrhoea. If gut support is needed, a cat-specific probiotic is preferable.

What does green or yellow stool mean?

Yellow may suggest bile or liver/gall-bladder issues; green can indicate rapid transit or ingestion of non-food items. Both warrant monitoring.

How can I boost my cat’s hydration if they have diarrhoea?

Ensure fresh water always available, add a pet-safe broth, switch to or add wet food, and monitor litter-box. Hydration aids recovery.

Can stress really cause diarrhoea in cats?

Yes. Emotional or environmental stress (new home, new pet, major change) can trigger gut responses and diarrhoea even without diet change.

Is fibre always good for diarrhoea in cats?

It depends. Some cases benefit from low-fibre, highly digestible diets; others respond to added fibre. It’s best guided by your vet.