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Why does my cat still have diarrhea after changing food back?

Updated On September 23rd, 2025

Pet's info: Cat | British Shorthair | Female | unspayed | 1 year and 7 months old

I did change my cats food and only after a week did she start showing symptoms of diarrhoea, I immediately changed back to her original food. However she still has diarrhoea and seems to have no control over her bowl movements. I have a kitten who has eaten the same things but has not exhibited any symptoms.

5 Answers

Most Helpful Answer

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Answered By Summer Walker, DVM, MS

Veterinarian

Published on July 11th, 2017

It is possible that the transition to the new food caused the diarrhea in Toothless. An abrupt transition back to the old food may not result in the diarrhea improving. It is always important to do a slow transition to a new diet, gradually mixing in more of the new food and less of the old food over the course of a week. This will help decrease the incidence of diarrhea in many cases. You may need to feed a bland diet (such as plain boiled chicken and rice) for a few days to allow the gastrointestinal tract to rest, and then slowly transition back to her original diet. If the diarrhea worsens (develops heavy mucus or blood), Toothless becomes lethargic or inappetant, then she should be seen by her veterinarian to rule-out internal parasites or an infectious cause.

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Other Answers

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    Answered By Susan England-Foster

    Veterinarian

    Published on

    I would recommend trying a probiotic. Sometimes when you switch a diet and it causes GI upset like diarrhea toothless will need antibiotics from a vet. I would recommend taking her to a vet if her diarrhea does not clear up with a probiotic. I would also recommend keeping her food the same since she seems to have a sensitive gastrointestinal system

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    Answered By Dr. Heidi DVM, CVA, CCRT, CVTP, CVSMT, CVCH

    Veterinarian, Certified Veterinary Acupuncturist, Certified Canine Rehabilitation Practitioner

    Published on March 25th, 2018

    I'm so sorry that Oliver and Lolly are having such a hard time with their diet change. There has been a lot of research with cat nutrition recently. Cats are obligate carnivores and cannot use the carbohydrates in dry food well, so they get converted to fat. We also think that cats that eat only dry food are chronically dehydrated and have a higher chance of developing kidney failure as well as other health conditions. So, there is research that canned food is healthier for them than dry food. However, we have to be careful changing a cat that is used to eating dry food onto a canned food diet. It is not normal for a cat to have diarrhea after a food change (especially not for 2 weeks!). I would recommend contacting your veterinarian to discuss what has happened. They may recommend a bland diet for a few days to resolve the diarrhea, then can hopefully give you a plan for a slow diet change to prevent further GI problems. Good luck! I hope that was helpful and that Oliver and Lolly feel better soon. Thanks for using Petco Pet Education Center, formerly Petcoach.

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    Answered By Rodrigo Roca, DVM

    Veterinarian

    Published on August 14th, 2017

    Hello, sorry to hear about Faith. His signs may or may not be related to his diet change. Yes, a sudden change in diet in a small kitten can lead to watery diarrhea which may cause them to feel quite ill. However, there are other causes such as ingestion of foreign material, parasites, and viral infection that could also cause the same signs. In general, Faith should be eating kitten food until she is fully grown or about 9-12 months in cats. So your intent was the right choice. If Faith continues to have a decreased appetite and is not feeling well in the next day, please have her evaluated by your veterinarian and look for any other causes of her diarrhea and decreased appetite. Best of luck and hope this helps.

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    Answered By Lauren Jones VMD

    Veterinarian

    Published on March 31st, 2017

    Oh no, Trico! Diarrhea all over the house is miserable for everyone! Typically, anytime you make any change in diet, do so by gradually mixing the old and new foods together over 5-7 days. There is a chance that either the new adult food has a different protein source to which Trico is sensitive, or that he has a virus or intestinal parasites. At this point, put Trico back on his kitten diet and take him to his vet for an exam with a stool sample to check for parasites. As a general rule of thumb, cats should continue to eat kitten food until they are 1 year old.

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