Two Easy Ways to Start Earning Rewards!
Become a member today!
Members-only pricing and offers, personalized care notifications, Vital Care points back on every purchase and more!
Already a member? Sign in
Become a credit card member today!
Earn 2X Pals Rewards points at Petco
when you use Petco Pay!
APPLY NOW
Learn More About Petco Pay Benefits

Cat on metronidazole: Explosive diarrhea normal? Keep giving meds?

Updated on September 23rd, 2025

Pet's info: Cat | Korat | Male | neutered | 13 years and 5 months old | 9.6 lbs

Hi, my cat has been having chronic loose stools and was put on metronidazole. After just one day of the antibiotics, he started to have explosive diarrhea. Is that normal and should I continue with the meds?

4 Answers

Most Helpful Answer

Answered By Jyothi Alagappan

Veterinarian

Published on June 2nd, 2018

Hi and thank you for using PetCoach. I am sorry to hear that Beau is having diarrhea. Since, Beau has only been on metronidazole for one day, I would continue it as it may not have started to work yet. It typically takes 24-48 hours to see any changes. However, if Beau stops eating, is lethargic or has blood in his stool, I would reach out to your veterinarian again and let them know. Beau may need another physical exam or other medications.

Here is an article on diarrhea in cats that may be helpful for you and Beau: https://www.petcoach.co/article/diarrhea-in-cats/

Good luck and I hope he feels better soon!

2Pet Parents found this answer helpful

Related Answers from Veterinarians

Answered By Jenny, DVM
Veterinarian
Published on December 30th, 2017
All you can do is continue the medication as previously directed--more doses should help, it just may be too soon to see right now. I would look at a local pet store for a feline probiotic to add to the food as this can help repopulate the normal bacterial population and possibly change her to a sensitive stomach formula food.
1Pet Parents found this answer helpful
Answered By Lindsey Edwards MVB, BSc, IVCA
Veterinarian
Published on December 21st, 2019
Without a full history as to why a diet change was prescribed it is impossible to recommend reverting back. Metronidazole can cause marked diarrhoea in patients which may be triggering the symptoms. I recommend continuing as prescribed until you can contact your Vets office to discuss the changes in her condition and decide the best way forward
1Pet Parents found this answer helpful
Answered By Stacey Anstaett, DVM
Veterinarian
Published on May 29th, 2019
My understanding of your question os taht you are concerned about your cat having loose bowel movements, her stool is loose like she has some mild diarrhea. Am I understanding you correctly? If so, then you can try adding a probiotic; there are some good ones formulated for cats. Ideally, take Chikoo to a veterinarian. If your vet diagnoses Giardia or an overgrowith of bacteria, often the medication metronidazole is prescribed. Metronidazole is not labeled for use in animals, though it has been used safely and effectively. See additional information here: https://cdn.ymaws.com/www.aavpt.org/resource/resmgr/imported/metronidazole.pdf

Thank you for asking PetCoach!
1Pet Parents found this answer helpful

Smart Picks for Smart Questions

Related Questions

Health & Wellness

My pet's diarrhea got worse on Metronidazole. Should I stop?

It could be that the diarrhea worsening is independent of the metronidazole as this drug does not help all cases of diarrhea, dependent on the cause. But since it is new it would be best to stop until you can speak with your vet. Has your kitty had a work up for these symptoms? Chronic vomiting and diarrhea are common symptoms of several things, but most notably GI disease. It would be abnormal for a cat to need chronic medication for vomiting unless there is a disease process there. Just to help a little, a work up for an older kitty with these signs could include bloodwork with thyroid testing, an abdominal ultrasound, and sampling if needed (dependent on ultrasound). If there is an underlying disease that can be treated your kitty may feel better and need less medications eventually. I hope this helps and thank you for using Petco Pet Education Center, formerly Petcoach!

Updated on September 23rd, 2025

Health & Wellness

My kitten has diarrhea. How quickly does metronidazole work?

I wouldn't be too hard on the vet in this case, because shelter vets are quite used to treating these cases and metronidazole kills most of the offenders for causing diarrhea. You are right to be concerned about dehydration and how quickly the treatment should work. In most cases the diarrhea will improve within a day of starting treatment. It may be 3-5 days before his stools are back to normal though. If the explosive diarrhea continues for longer than a day after starting treatment and/or the kitten seems to be very depressed/inactive, then it would be best to return him to the shelter. There are some cases that require hospitalization, but I can assure you that most are treated well at home with the prescribed protocol. For now, I recommend following the veterinarians directions and calling the vet tomorrow if he seems to not be getting any better, or seems to be getting worse. Below is a link to an article about diarrhea in cats that may be helpful. https://www.petcoach.co/article/most-common-causes-of-diarrhea-in-cats/ I hope that helps and the foster kitten gets better soon.

Updated on September 23rd, 2025

Cat's diarrhea worse on meds, now weak. Should I give Pedialyte?

I am sorry Damian does not feel well. I would recommend recontacting the vet to let them know Damian feels worse. Typically metronidazole works with in 24-48 hours. Typically if he is having liquid diarrhea he is not constipated. I would make sure a fecal is negative for parasites like coccidia. He might need deworming for coccidia since he is you. I would feed him the new food and you can start with a small amount of pedialyte however if he is still not improving I recommend taking him back to a veterinarian for more testing like bloodwork.

Updated on September 23rd, 2025

Health & Wellness

My dog has diarrhea. How long until metronidazole starts working?

Hi there. In my experience, it often takes 48 hours or so to see improvement in diarrhea after starting metronidazole. Full resolution of the problem may take another 2-3 days from there. So if Jake's diarrhea seems to be improving and his appetite is better, this is a good sign. I would continue with the current treatment plan prescribed by your veterinarian. If his diarrhea has not resolved in another 2-3 days, then I would recommend taking him back in for a recheck to see if some other type of treatment is needed.

Updated on September 23rd, 2025

Is soft puppy stool normal after metronidazole for diarrhea?

Hi! I would say that it is likely ok. Sometimes it takes a bit longer to see results. If it is just soft and Snowball is otherwise fine, I would just give it a few days before getting concerned. Keep in mind that metronidazole is not always a curative medication for diarrhea but rather an antibiotic with anti-inflammatory properties that help with colitis. This means that it will not treat an underlying disease every time. Perhaps try a few days on a bland diet mostly composed of boiled chicken or turkey and rice. If no resolution within a few days, it may be appropriate to start her on a probiotic or try a different medication such as Tylosin. Best of luck with her!

Updated on September 23rd, 2025

Food & Nutrition

My cat has Giardia, diarrhea, and isn't improving on meds. What now?

Hi from Bangladesh! Don't worry, it may take a few more days to see improvement. You may also try a bland diet of boiled chicken, rice, and plain canned pumpkin (not the pie filling) to help firm up the stool. Using a probiotic for cats and dogs can help as well. Hope this helps!!

Updated on September 23rd, 2025

Health & Wellness

My cat has chronic diarrhea, meds didn't work, fecal negative. Is it serious?

Hello and welcome back! Prednisolone not working suggests that IBD is not the problem. Metronidazole is a broad spectrum antibiotic and treatment for giardia, therefore likely the problem wasn't a bacterial or giardia infection. A negative fecal rules out other parasites like worms or coccidia. If Beau has hyperthroidism then the diarrhea could be related to this, and tweaking of the medication might be required. He still could have cancer in the GI tract (lymphoma) which doesn't always cause an obstruction or pain, especially not right away. He could also have food allergies, or liver disease, or pancreas disease. There would be pain with an obstruction, and clinically this doesn't sound like an obstruction, but you can have no pain with cancer. Best of luck with Beau.

Updated on September 23rd, 2025

Have A Vet Question?

Book an appointment with the pros – our expert vets are here to help.

Share