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My puppy has diarrhea. How long for stool improvement after new food?

Updated On September 23rd, 2025

Pet's info: Dog | Australian Shepherd | Female | spayed | 6 months and 12 days old | 35 lbs

How long after switching a new food should I expect stool improvement? My puppy has had diarrhea for 2 weeks, we went to the vet, neg fecal test, she was dewormed and given metronidazole last week. After the meds we still saw no improvements. I was feeding her victor which i read could cause diarrhea due to high protein (38%) so yesterday I switched her to 4health lamb puppy food. Even before the switch of foods she had liquid stool and it has not stopped yet. I gave her a dogAntidiareah liquid

1 Answer

Most Helpful Answer

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Answered By Linda G, MS, DVM

Veterinarian

Published on February 1st, 2019

Hello. It might take 3-5 days minimum to see if the diet will work. Often, when we suspect a problem is due to a food sensitivity, the food trial is 6-8 weeks. So, it can take time to see if the diarrhea subsides. Just make sure she is drinking plenty of water & not losing weight. Also, make sure you communicate to your vet that the diarrhea did not respond to the metronidazole. She may want to continue testing, switch to another antibiotic or medication. I would also start her on a good probiotic for dogs like Proviable or FortiFlora, both should be available at most pet retailers. Thanks for using Petco Pet Education Center, formerly Petcoach.

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