Had a similar experience with our golden pup. He had a reaction to a popular flea/tick medication… our vet said it would take 3-6 months to get out of his system, hopefully without long term systemic damage. We used vetri probiotic bd and royal canine for gi (prescription only) and an antihistamine shot initially. He responded well, diarrhea stopped, and his appetite improved…. Would not recommend corn in any form… too harsh for an already up set gi tract… but what worked for us was a vetri science vitamin supplement to improve his appetite, as well as fresh foods ( only organic blue berries, apple slices w/o skin no seeds!, cucumber, banana, carrots, boiled chicken, boiled turkey and of course peanut (crazy Richard’s brand) only peanuts no additives. In addition to his Royal canin kibble. So far so good…. He was 2yrs in July’21 and about 90 lbs… hope this helps…
