Cat diarrhea is looser, wetter, and more frequent than your cat’s normal stool, and it can range from slightly soft to completely watery. Most cats poop at least once a day, producing firm, formed stool that holds its shape in the litter box. If what you’re finding looks more like a puddle, a cowpat, or soft-serve ice cream, your cat likely has diarrhea.
What Normal Cat Stool Looks Like
Veterinary professionals use a six-point fecal scoring system to grade stool consistency, and it’s a helpful mental framework even at home. On that scale, scores of 3 and 4 are considered normal: the stool is firm, segmented or log-shaped, and holds together when you scoop it. It should be a deep brown color and leave minimal residue on the litter.
At the dry end of the scale (score 6), stool looks like small, hard pellets that crack or crumble when pressed. That’s constipation. At the wet end (score 1), stool is completely watery with no shape at all, which is severe diarrhea. Anything softer than a formed log that loses its shape easily, leaves a wet smear on the litter, or coats the scoop falls into diarrhea territory.
Signs You Might Spot Outside the Litter Box
You won’t always catch diarrhea in the litter box itself, especially if your cat uses clumping litter that absorbs moisture quickly. But your cat’s body often gives you clues. Soiled or matted fur around the back end is one of the most obvious. Cats are meticulous groomers, so visible staining or wetness near the tail almost always means stool was too loose to pass cleanly.
You might also notice your cat scooting on the floor, licking its rear end more than usual, or suddenly having accidents outside the litter box. Diarrhea can come on urgently, and even a well-trained cat may not make it in time. Stool stains on bedding, furniture, or near the litter box entrance are worth investigating.
Color and Texture Clues
The color and contents of your cat’s stool tell you a lot about what’s going on. Normal stool is chocolate brown. Here’s what other colors can mean:
- Yellow or greenish: food may be moving through the gut too quickly to be fully digested.
- Black or tarry: could indicate digested blood from higher up in the digestive tract. This warrants prompt attention.
- Bright red streaks: fresh blood, usually from the lower intestine or colon.
- Pale, gray, or greasy-looking: may point to problems with fat digestion.
Mucus coating on the stool, visible food chunks, or an especially foul smell (worse than usual) are also signs the digestive system isn’t working normally. A single soft stool can happen to any cat, but a pattern of abnormal color or texture over multiple bowel movements is meaningful.
Increased Frequency and Urgency
Cats with diarrhea typically go more often than their usual once-a-day pattern. If you’re scooping the box and finding three, four, or more deposits in a day, or if your cat keeps returning to the box in short intervals, that increased frequency is itself a sign of diarrhea even if the stool isn’t completely liquid. Straining in the box is also common, and owners sometimes mistake it for constipation when it’s actually the opposite: the cat is trying to pass irritated, inflamed bowel contents.
How to Check for Dehydration
Diarrhea pulls water out of the body, and cats can dehydrate faster than you’d expect, particularly kittens and older cats. You can do a quick check at home with the skin tent test: gently pinch and lift the skin between your cat’s shoulder blades, then release it. In a well-hydrated cat, the skin snaps back flat immediately. If it stays tented or returns slowly, your cat is likely dehydrated.
This test isn’t perfect. Very thin cats can show tenting even when hydrated, and overweight cats may seem fine when they’re not. Age matters too: older cats naturally have less elastic skin. As a backup check, slide a finger along your cat’s gum line. Healthy gums feel slick and moist. If they feel dry, sticky, or tacky, that’s another sign of fluid loss. A cat that is both having diarrhea and showing signs of dehydration needs veterinary care quickly.
Acute vs. Chronic Diarrhea
Veterinarians classify diarrhea lasting less than three weeks as acute. This is the most common type and often resolves on its own or with minor dietary adjustments. Common triggers include sudden food changes (switching brands or flavors without a gradual transition), eating something they shouldn’t have, stress from a move or new household member, or a mild stomach bug.
Diarrhea that persists beyond three weeks is considered chronic. Chronic diarrhea points to an underlying issue that won’t simply go away: food intolerances, inflammatory bowel conditions, parasites, or other systemic problems. If your cat’s stool has been consistently soft or watery for weeks, that’s not just a sensitive stomach. It needs investigation.
Figuring Out Which Cat in a Multi-Cat Home
If you have multiple cats sharing litter boxes, identifying the culprit can be tricky. The most reliable approach is temporary separation: confine each cat to a different room with its own litter box for a day or two and check the results. You can also try adding a tiny amount of a nontoxic food marker (like a small piece of crayon shaving mixed into wet food) to one cat’s meal and watching for it in the stool. Monitoring who has soiled fur, who seems lethargic, or who is visiting the box most frequently can also narrow things down.
When Diarrhea Signals Something Serious
A single episode of soft stool in an otherwise normal, playful cat is rarely an emergency. But the timeline and accompanying symptoms matter. If frequent liquid or semi-liquid stools persist for more than two days, it’s time for a veterinary visit. If your cat also shows poor appetite, lethargy, vomiting, abdominal pain, fever, or weakness alongside the diarrhea, the situation is more urgent.
Bloody diarrhea, whether bright red or black and tarry, warrants immediate attention regardless of how long it’s been going on. Kittens deserve extra caution because their small bodies have fewer fluid reserves; even 24 hours of watery diarrhea in a young kitten can become dangerous. If your cat doesn’t improve within four days even with a bland diet and otherwise normal behavior, further evaluation is typically needed to rule out parasites, infections, or chronic conditions.