Ever since I got my puppy, she has not really had solid poop. I told the vet about it & they said to slowly change her dog food, well I did, but didn't really see any changes. She only vomited the new food up. So I went back to the other dog food and she is fine, but still her poop is runny. When she got checked out at the vet, they said she was very healthy. So do I just need to keep changing her food until I can find one that works for her?
Have you taken a stool sample to the vet so they can check for worms? Your not going to see the worms unless meds are given and they pass through. The vet can look at the stool sample under a microscope and determine what types, if any worms are present. Also, any food you give has to be a gradual change. Not something that happens overnight or in 2 days even if you did switch your pup back to the dog food they originally ate.
I'm with Halo, get a sample of the runny poop into a plastic ziploc bag and take it to the veterinarians with you. Also, what food are you feeding her now, and what did you try swapping her over to? If you were feeding Purina dog chow, and you swapped her over to another lower grade food like Pedigree or Ol' Roy, you probably won't see any changes whatsoever, since none of those foods is a high quality feed.
definitely have a stool sample checked for worms . even if you did have one already do it again. sometimes depending on the stage of the worms cycle you may not see them under the microscope the first time around. you could try mixing live culture yogurt in with her food. that will help clear up the diarrhea.
i'd say check for worms, too. you can also try feeding her less food at one time more frequently, puppies can get diarrhea just because they are puppies. their little systems have a hard time with certain amounts of food.