Stool shape and color often change before any other sign of illness. A quick look each time you scoop catches problems while they’re still small.
The Bristol stool scale
The Bristol Stool Scale was made for people, but it works just as well for cats. Telling your vet “it went from a 4 to a 6” is clearer than “softer than last week.”
The Bristol Stool Scale adapted for cats
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| Score | Shape | What It Means |
|---|---|---|
| 1 | Hard pellets, like small stones | Severe constipation |
| 2 | Lumpy sausage shape | Mild constipation |
| 3 | Sausage with cracks | Normal range, slightly firm |
| 4 | Smooth sausage or snake | Ideal |
| 5 | Soft blobs with clear edges | Normal range, slightly soft |
| 6 | Mushy, fluffy pieces | Mild diarrhea |
| 7 | Watery, no solid form | Diarrhea |
Most healthy cats sit at a 3 or 4. If your cat is eating and acting normally, a 5 is nothing to worry about.
What color tells you
Normal stool is brown. If it turns black, red, or grey, take a closer look.
What different stool colors may indicate
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| Color | Status | Possible Causes |
|---|---|---|
| Brown | Normal | Healthy digestion |
| Dark brown | Usually normal | High-protein diet |
| Black, tarry | See vet promptly | Upper GI bleeding, iron supplements |
| Red, bloody | See vet | Lower GI bleeding, anal fissures, colitis |
| Yellow, orange | Monitor; see vet if it persists | Liver or gallbladder issues, food intolerance |
| Green | Monitor; see vet if it persists | Bile changes, eating grass, fast transit |
| White, grey | See vet | Bile-duct blockage, exocrine pancreatic problems |
| Mucus coating | Monitor; see vet if it persists | Colon inflammation, parasites |
What you might find in the stool
Small white segments like grains of rice can be tapeworm. Thin, spaghetti-like worms can be roundworm. Bag a sample and bring it to your vet.
A little hair in the stool now and then is normal, swallowed during grooming. A sudden increase can mean your cat is grooming more than usual.
If you see string, ribbon, or dental floss coming out of your cat’s rear, never pull it. The other end may still be inside, and pulling can cut the intestine. Get to a vet the same day.
Soft stool that won’t settle
One soft stool after a treat, a new food, or a stressful day is usually nothing. Soft stool on and off, or for more than two to three weeks, is a longer-term gut problem, and these are the common causes.
- Food sensitivity, common in younger cats. Some cats react to ingredients in their food, and a change of food on your vet’s advice often clears it up within a few weeks.
- Parasites such as Giardia cause ongoing soft stool that looks like ordinary diarrhea. It won’t clear on its own and needs treatment.
- Chronic gut inflammation is considered once food and parasites are ruled out. Sometimes a biopsy is needed to confirm it.
- Intestinal lymphoma is mostly seen in older cats, with slow weight loss, vomiting, and soft stool.
Your vet typically starts with a fecal panel, bloodwork, and a diet trial before moving to imaging or biopsy. Don’t wait three months hoping it resolves on its own.
Diet transitions and stress
Even a perfectly good new food can cause a few days of softer stool if the switch is fast, because the gut needs time to adjust. Take 7 to 10 days. Start at 25% new food, then 50%, 75%, and finally 100%. Rushing the switch is the most common cause of soft stool, and the easiest to avoid.
Boarding, a move, a new pet, or visitors can also loosen stool for a while. If your cat is eating, drinking, and acting normally, give it a few days.
What to watch changes with age
- Kittens dehydrate fast. A kitten under 6 months with diarrhea can dehydrate quickly. With vomiting or lethargy, go to the vet the same day.
- Watch for change in adults. Most adult cats go once or twice a day, on a steady rhythm. If a cat who goes daily suddenly stops for several days, or goes far more often, take note.
- Seniors tend toward constipation, often because of something else, such as kidney disease, not drinking enough, or arthritis that makes squatting hard. A senior who hasn’t passed stool in 48 hours, or strains without producing, should see a vet before you reach for over-the-counter fiber.
When to see a vet
A one-off change that isn’t severe can be watched for a day.
See a vet
- Bristol 1–2 (constipation) or 6–7 (diarrhea) lasting more than 24 hours
- Yellow, green, or another abnormal color that persists
- Small blood streaks without other signs
- Mucus that lasts more than a day or two
- Soft stool that has been going on more than 2–3 weeks
- Pooping outside the litter box with nothing changed at home
Go the same day, or to an emergency vet
- Black tarry stool combined with pale gums, weakness, or collapse
- A lot of bright red blood with constant watery diarrhea, more urgent with vomiting
- A red tube of tissue sticking out of the anus (rectal prolapse)
At the clinic where I work, constipation is one of the most common reasons cats come in. Many owners bring their cat in after about two days of finding no stool when they scoop the litter box, and by then the vet often needs to give an enema. Enemas made for people are toxic to cats, so never try one at home; the constipation guide explains more.
A straining male cat may be blocked
A male cat who keeps straining in the litter box may be constipated, or he may be unable to pee. A blocked urethra causes the same straining and can be fatal within 24 to 48 hours.
A blocked cat passes only a few drops or nothing, cries in the box, keeps licking down there, and has a hard belly. If you can’t tell whether he’s trying to poop or pee, treat it as a blockage and go to the emergency vet now.
Bringing a stool sample to the vet
If your cat has gut symptoms, bringing a fresh sample can save a second trip.
- Fresher is better. Within 12 to 24 hours is best. Older than that and parasites can be missed.
- Refrigerate, don’t freeze. Freezing can affect Giardia testing.
- A little litter stuck on is fine. Don’t rinse it, just bag it.
- About the size of a pea is enough.
Logging stool with Furwise
Looking at stool every day is easy. Remembering what it looked like last week is the hard part. Take a photo in Furwise and the app estimates a Bristol score, checks the color, and logs how often your cat goes. When something looks off, you have the earlier records to show your vet.
Frequently Asked Questions
What does healthy cat poop look like? A Bristol 3 or 4, smooth or slightly cracked, brown, and holding its shape. Rock-hard, watery, or with mucus or blood is not normal.
How often should a cat poop? Once or twice a day for most adult cats. Some go every other day on a very digestible food, which can be normal. Several days without stool, or a sudden jump in how often, is worth noticing.
How long can a cat go without pooping? Up to 48 hours is usually fine, especially if your cat has been eating less. Past 48 to 72 hours, or straining without producing anything, see a vet. Senior cats and cats with kidney disease constipate more easily, so keep a closer eye on them.
Why does my cat have soft poop after switching food? The gut needs time to adjust to a new food. Switching gradually over 7 to 10 days usually prevents soft stool. A little softness in the first week is normal. If it hasn’t settled after two weeks, the food may not suit your cat.
Why is my cat pooping outside the litter box? It can be physical. Constipation, diarrhea that comes on too fast, or painful pooping can put a cat off the box. It can also be the setup, such as a dirty box, a recent move, tension between cats, or a new litter. If it started suddenly and comes with straining or soft stool, treat it as a health problem first.
Can I give my cat probiotics for soft stool? They may help, but results vary a lot with the strain, the amount, and what’s causing the soft stool. If you try one, choose a product made for cats, not human yogurt or an unverified supplement. If soft stool has lasted weeks, a probiotic doesn’t replace a vet workup.
References
- Lewis SJ, Heaton KW. (1997). Stool form scale as a useful guide to intestinal transit time. Scandinavian Journal of Gastroenterology, 32(9), 920-924.
- Marsilio S, Freiche V, Johnson E, et al. (2023). ACVIM consensus statement guidelines on diagnosing and distinguishing low-grade neoplastic from inflammatory lymphocytic chronic enteropathies in cats. Journal of Veterinary Internal Medicine, 37(3), 794-816.
- Pilla R, Gaschen FP, Barr JW, Olson E. (2025). Probiotic, prebiotic, synbiotic, and postbiotic supplementation in cats: a systematic review. Journal of Small Animal Practice.
- Whittemore JC, Stokes JE, Price JM, Suchodolski JS. (2017). Effects of a synbiotic on the fecal microbiome and metabolomic profiles of healthy research cats administered clindamycin. Journal of Feline Medicine and Surgery, 21(8), 770-779.
- Washabau RJ, Day MJ. (2013). Canine and Feline Gastroenterology. Elsevier Saunders.
- Cornell Feline Health Center. (2024). Gastrointestinal Parasites of Cats. Cornell University.
- International Cat Care. (2023). Digestive System Problems in Cats. icatcare.org
