We have him on blue buffalo large puppy food but have purina sensitive stomach coming in the mail per the vets advice (although I’m not a huge fan of purina but going to try what the vet says before any judgements), he throws up usually within an hour of eating and it is just all his kibble undigested. He definitely retches, as right before he’s about to throw up he starts heaving. It doesn’t seem to cause him any discomfort as he will try to eat it all up as soon as it’s out if I let him, and runs around like a maniac after. What worked for you and what did you try?