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Why does my cat still have liquid diarrhea after antibiotics?

Updated On September 23rd, 2025

Hi, cat Alfie (5yrs old, large, neutered male) has been healthy until last Friday when he developed bad diarrhoea. Vet on Monday, for an antibiotic injection. Back to vet Tuesday for 5 day course of general antibiotic tablets. He is eating and drinking (I have him on light food from the vet)..but he still has very bad diarrhoea. Even if he moves a little, he poos. Liquid brown poo. It has been nearly a week now. What could it be and what treatment would work?

1 Answer

Most Helpful Answer

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Answered By Dr. Leigh, DVM

Veterinarian

Published on February 2nd, 2017

Alfie could have a parasite, infection, inflammatory bowel disease, hyperthyroidism, liver/kidney disease, etc. Since it has been a week, it would be a good idea to have full blood work, fecal test, and x-rays done to rule out potential causes. I would also recommend switching to a hypoallergenic diet, like d/d, and see if that helps. A medication called Proviable KP may also help. If your vet didn't already prescribe Metronidazole (Flagyl) than that could be tried, too. If the diarrhea persists than an intestinal biopsy may be needed.

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