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My dog still has diarrhea after fenbendazole. What to do now?

Updated on September 23rd, 2025

Pet's info: Cat | Mixed Breed | Male | 2 lbs

John has have diarrhea so I gave him fenbendazole, 50mg each day for 3 days, but he still have diarrhea now 3 days after the 3-day treatment. What to do now? Another 3-day treatment of Fenbendazole, or start 7-days treatment of Metronidazole?

3 Answers

Most Helpful Answer

Answered By Dr. Davis

Veterinarian

Published on September 19th, 2017

The diarrhea may be from his diet or stress as it has not improved. The fenbendazole is for treating parasites. There is no reason to do that again. Using a course of metronidazole is fine but I would make sure he's on a bland diet, and you can add a tablespoon of canned pumpkin at each meal to increase the fiber and bulk up the poop. If he should stop eating or the diarrhea continues please take John in for a veterinary exam, fecal test and treatment. Thanks for using Petco Pet Education Center, formerly Petcoach to help you care for John.

2Pet Parents found this answer helpful

Related Answers from Veterinarians

Answered By Laura Johnson VMD
Veterinarian
Published on October 5th, 2018
Hi, thanks for using Petco Pet Education Center, formerly Petcoach! Poor Simba!

I would consider a course of a probiotic like Purina Fortifkora or Nutramax Proviable. I would also call your vet and ask for a prescription intestinal diet to feed for a week or two. Also drop off a stool sample to check for worms. Chicken and rice is okay but he may need something that will help him quicker. If the probiotic and diet don’t help then he should be rechecked.

Good luck!
1Pet Parents found this answer helpful
Answered By Laura Johnson VMD
Veterinarian
Published on July 7th, 2018
Hi, thanks for using Petco Pet Education Center, formerly Petcoach! Poor Gnocchi (very cute name!)

Giardia AND the medication can cause loose stool. If he continues to have loose stool I would start a bland diet. Boil chicken or hamburger and mix with rice. Feed 1 cup per 20 lbs per day. If it continues through the weekend call your Vet monday and see if they will add metronidazole in for the diarrhea. It can also help clear giardia. I usually prescribe both together. Also be careful handling his stool as people can get giardia as well!

I wish Gnocchi the best!
1Pet Parents found this answer helpful

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