Dog Is Sick. Help!?

he has to have a lot of time and really small quanities of the new food to get use to it. this happened with my husky when i put him on purina dry a few yrs ago, he was pooping everywhere and vomiting because of the change. u have to intoduce him by adding just a tiny bit to his regular food daily until the switch is gradually made within a month or so. for now u can give him a tsp of pepto bismal or kaeopecdade every 3 or 4 hours for a day or so and give him lots of fresh water or some kind of sports drink like gatorade to get fluids and help his stomach settle down.lay off the new food for a few days then just add about a 1/4 cup or less to his food to see if he can tolerate the change. he might not and like my husky i just got rid of the purina and he gets canned wet meat,ole roy dry or kibbles an bits and also i feed him what we eat at meal times. he is almost 8 yrs old and a big ole mooch but he is pretty healthy at 105 lbs. good luck