Hi Chandra-
Sorry to hear about your pup with chronic diarrhea. Can I assume you have done fecal tests to rule out parasites? Giardia can be cyclical and tough to get rid of.
High fiber food and Panacur helped my dogs get over chronic diarrhea.
However, one of my cats has presumed IBD and I tried several different foods. After going to an Internal Medicine Specialist, he is stable by feeding him a novel protein Rx food, added fiber to his wet food, Tylosin powder and probiotics. He also had a series of Vitamin B shots that really helped.
He eats Royal Canin rabbit or venison both dry and wet.
Think about going to an Internal Medicine Specialist if you feel your regular vet isn’t finding a solution. Good luck!
