What cat diarrhea looks like

Cat diarrhea in the litter box appears as soft, unformed stool that clumps poorly or not at all. Instead of the firm, round pellets of healthy cat waste, you will see material that ranges from paste-like to liquid, often sticking to the litter or the box itself. The stool may look wet, muddy, or soupy depending on how severe the diarrhea is.

The color can vary widely. Diarrhea may be brown, tan, yellow, or even greenish, and sometimes contains visible mucus or blood streaks. If your cat has been eating a particular food, the color often reflects that — for example, red-tinged stool after eating red-colored treats, or gray stool after eating fish-based food. Blood in the stool is always worth noting when you talk to a veterinarian, even if the diarrhea seems mild otherwise.

You may also notice that the litter box smells worse than usual. Diarrhea has a stronger, more pungent odor than normal cat waste because the stool spends less time in the colon, where water is normally absorbed and odor is contained.

Key Takeaways

  • Healthy cat stool is firm and clumps well; diarrhea is soft, pasty, or liquid and does not clump.
  • Diarrhea color ranges from brown to yellow to greenish, and may contain visible mucus or blood streaks.
  • A single episode of soft stool is often not serious, but diarrhea lasting more than a day or two warrants a veterinary call.
  • Cats with diarrhea may use the litter box more often than usual and may have accidents outside the box if they cannot reach it in time.

How often your cat is using the box

A cat with diarrhea typically uses the litter box more frequently than normal. Healthy cats usually defecate once or twice a day; a cat with diarrhea may go three, four, or more times daily. You may notice your cat making more trips to the box, spending more time there, or seeming restless or uncomfortable during or after use.

If the diarrhea is severe or comes on suddenly, your cat may not make it to the box in time and may have accidents on the floor, in corners, or on bedding. This is not a behavior problem — it is a sign that the stool is moving through the digestive system too quickly for your cat to control.

Differences between mild and severe diarrhea

Mild diarrhea appears as soft or slightly loose stool that still holds some shape. The litter may clump somewhat, though not as well as with normal stool. Your cat may seem otherwise normal — eating, drinking, and playing as usual. Mild diarrhea lasting one or two days is common and often resolves on its own, especially if your cat recently ate something unusual or experienced a minor dietary change.

Severe diarrhea looks like liquid or nearly liquid stool that does not clump at all and may pool in the litter box. You may see mucus, blood, or undigested food particles. A cat with severe diarrhea often shows other signs: lethargy, loss of appetite, vomiting, or straining in the box. Severe diarrhea lasting more than a day, or any diarrhea accompanied by vomiting or blood, should prompt a call to your veterinarian.

What causes diarrhea and when to watch for it

Common causes of cat diarrhea include sudden food changes, eating something the cat should not have eaten, food sensitivities, intestinal parasites, and bacterial or viral infections. Stress, antibiotics, or other medications can also trigger loose stool. In many cases, a single episode of soft stool is not a sign of serious illness.

Watch for diarrhea if your cat recently started a new food, got into the trash, or was exposed to a new environment or stressor. If the diarrhea continues for more than two or three days, if it is accompanied by vomiting, lethargy, or loss of appetite, or if you see blood or mucus in the stool, contact your veterinarian. Kittens, senior cats, and cats with existing health conditions are more vulnerable to complications from diarrhea and should be seen sooner.

Keeping the litter box clean when your cat has diarrhea

When your cat has diarrhea, scoop the box at least twice daily, or more often if needed. Diarrhea stool sticks to litter and the box sides more readily than normal stool, so you may need to remove clumps and soiled litter more frequently. Wash your hands after scooping, especially if you see blood or mucus.

Consider switching to a non-clumping litter temporarily if you use clumping litter, because diarrhea stool can be harder to remove cleanly from clumping varieties. Some owners find that paper-based or pelleted litters work better during bouts of loose stool. Once the diarrhea resolves, you can return to your regular litter.

If your cat is having accidents outside the box because the diarrhea is severe, place additional litter boxes in areas where accidents are happening. This gives your cat more options and reduces stress about reaching the box in time.

When to contact a veterinarian

A single episode of soft stool that resolves within a day usually does not require a veterinary visit. However, contact your veterinarian if diarrhea lasts longer than two or three days, if it is accompanied by vomiting, if your cat is not eating or seems lethargic, or if you see blood or mucus in the stool. Also call if your cat is straining in the box, seems to be in pain, or is having frequent accidents outside the box.

Kittens under six months old, senior cats over ten years old, and cats with diabetes, kidney disease, or other chronic conditions should be seen sooner — within a day of diarrhea starting. When you call, describe what the stool looks like, how long it has been happening, and whether your cat is showing any other signs of illness. This information helps your veterinarian decide how urgently your cat needs to be seen.

Frequently Asked Questions

Is it normal for cat stool to be soft sometimes?

Occasional soft stool is normal and usually not a concern, especially if it happens once and your cat seems fine otherwise. However, if soft stool becomes the pattern — if most bowel movements are loose or unformed — that warrants a veterinary check to rule out food sensitivities, parasites, or other issues.

What color diarrhea means my cat needs to see a vet right away?

Red or dark red stool suggests blood in the intestines and should be reported to your veterinarian, though it is not always an emergency if your cat is otherwise acting normal. Black or tarry stool is more concerning and may indicate bleeding higher in the digestive tract — call your vet the same day. Yellow or greenish diarrhea is usually less urgent unless it is accompanied by vomiting or lethargy.

Can I treat cat diarrhea at home?

Mild diarrhea often resolves on its own within a day or two, especially if you avoid making sudden food changes and may support your cat has access to fresh water. Do not give your cat over-the-counter antidiarrheal medications without veterinary guidance — some are unsafe for cats. If diarrhea persists or worsens, your veterinarian can prescribe appropriate treatment based on the cause.

Does diarrhea mean my cat has worms?

Diarrhea can be a sign of intestinal parasites, but it has many other causes — food changes, infections, stress, and food sensitivities are common. Your veterinarian can test a stool sample to check for parasites and recommend deworming if needed. Even indoor cats can have parasites, so testing is worth doing if diarrhea lasts more than a few days.