In my opinion and experience Eukanuba is not as great a dog food as everyone seems to think. Innova and Nutro brands to me are better. There is a possibility that the dog is allergic to the new food. However, it could have worms or be having a reaction to his vaccines even if they were a while ago. I almost lost my male lab to his rabies vaccine with similar symptoms only the vomiting was more than occasional. Make sure the dog has plenty of water and stays hydrated. Even supplementing with Pedialite is a good idea. It is harder than you think to rehydrate a dog. Check his gums if they are pale he may have worms. Also, check his capillary refill time by pressing on his gums (easiest on the area about his top canine tooth) if he is getting dehydrated or has worms the refill time will be slow. A slow refill will be if you take your finger away and can watch it refill over the span of 1 or 2 seconds. If it's quick it will probably refill while you are still pulling away your finger. Personally I hate vets and don't like to bring my animal there but use your good judgement and decide on that based on your own ideals.
