Upset tummy from food change?

Q: We recently switched our 5 month old Pomsky puppy's food. Per our vet's instructions, we weened him off the old food and slowly into the new food over the last 10 days or so. He seemed to be doing great, but we are on his second day now where he is fully on the new food and now he has diarrhea. He seems fine otherwise. No vomitting or visible loss of energy, nose is still wet. Just some loss in appetite, which makes sense. What should I do to help his tummy and gain back his normal appetite?

A: There likely is another cause since you changed properly. As long as he feels good you can try Pepto Bismol 0.5 ml per pound body weight 2-3 times a day for a couple days and let me know.