You could get another vets opinion if you don't feel this one is giving you complete and accurate information.

Until Dusty, I never had the experience you speak of. He was constantly throwing up as a puppy. Sometimes it was so loose and watery and then other times yellow and foamy. But the vet said he could not find anything wrong and it was probably some food allergy.

I started to pay attention to his diet more diligently. I discovered it was liver he was allergic to. I use to give both Dixie and Dusty Bil-Jac liver treats for training. Dixie never had a problem and loved them so I figured Dusty would too. Every time he got liver treats, he would throw up. Once I believed it to be the liver, I stopped giving it to him and the throwing up stopped. Then to test the theory I gave him one day and sure enough he threw up again. He has not had liver for over 1/2 a year and he is doing great!

Perhaps a food such as California Natural would help since the ingredients list is very limited. But ultimately you need to feel comfortable with your vet and his recommendation.