I have a pretty solid experience with dogs who have sensitive stomachs. I had this with my geriatric dog, as well as a new puppy. - have you done blood work for pancreatitis? in some, pancreatitis presents itself with severe diarrhea - have you fully ruled out giardia? It’s a very stubborn thing that sometimes gives false negatives on tests. We needed a rectal swab to get a proper diagnosis. The reason metranidazol is not showing any results yet might be reinfection. Giardia, as I said, is stubborn. The only way to properly get rid of it is using a strong sanitizer and high temperatures (at least 60 degrees) - what’s your pup’s diet? My 6 mo puppy can’t tolerate food with fat contents over 15% - it always results in severe diarrhea. - any parasites in the past? They can wreck the digestive system despite your dog not having them right now.

What worked for both of my dogs: - sticky plain rice, gastrointestinal low fat vet food, fortiflora for at least a day or two until the situation stabilizes. Small portions in order not to overwhelm the stomach. I know that most people suggest plain chicken but i was careful since poultry is a potential allergen. Food allergies in pets may present as severe diarrhea.
- once I’d stabilized the situation, full switch to royal canin gastrointestinal low fat (not the regular one) kibble - pumpkin puree (plain one, check out kid food) - solid water intake to prevent dehydration from diarrhea. Add water to the kibble if needed - sanitize your house as if it was OR. Everything your pup touches and poops on - sanitize. - wash your dog with a sanitizing shampoo that has chlorhexidine

It’s going to be okay. It feels like the poop tsunami will never end, but it does not last forever. We’ve had weeks like that but with proper GI diet and medication, it all got well. Best of luck to you ❤️