Updated October 14, 2026. Fact-checked against veterinary sources; review by a licensed veterinarian is in progress. See our editorial policy.
Quick answer: Diarrhea is common in kittens, often from parasites, diet changes, or stress after adoption. But kittens dehydrate quickly, so diarrhea lasting more than a day, or with lethargy, vomiting, poor appetite, or blood, needs a vet promptly. Unvaccinated kittens with vomiting and diarrhea may have panleukopenia, a serious viral infection.
Signs to watch
- Soft or watery stool
- Straining or accidents
- Mucus or blood
- Soiled fur around the tail
Common causes
- Intestinal worms, Giardia, coccidia, or Tritrichomonas
- Sudden diet changes after adoption
- Overfeeding or cow’s milk
- Viral infections including panleukopenia
- Stress
Go to a vet or emergency clinic right away if
- Lethargy, weakness, or not eating
- Vomiting with diarrhea
- Blood in stool
- Sticky gums or sunken eyes
- An unvaccinated kitten with vomiting and diarrhea
Safe home care while you arrange a visit
- Keep feeding the kitten food, in small frequent meals
- Keep fresh water available
- Bring a fresh stool sample to the vet
- Keep the kitten’s rear clean
What to avoid
- Cow’s milk
- Human anti-diarrhea medicines
- Withholding food
Can you ask a vet online about this?
Online vet services can be helpful for deciding how urgent a problem is, getting general advice, and follow-up questions. But they have limits:
- A vet can’t examine your kitten, listen to the heart and lungs, or run tests over video
- In many US states, a vet must have examined your kitten in person before prescribing medication. Rules vary by state and are changing
- For any emergency sign listed above, go directly to an emergency clinic rather than waiting for an online reply
Have your kitten’s age, weight, medications, and photos or video of the problem ready to make any consultation more useful.
More: coccidia in cats and kittens.
Sources
- Merck Veterinary Manual: Care of kittens
- Cornell Feline Health Center: Kitten care
- Merck Veterinary Manual: Feline panleukopenia
- Companion Animal Parasite Council (CAPC): Guidelines for kittens
This article is for general education and is not a substitute for care from your own veterinarian. Learn about The Pet Vet and our editorial policy.