A dog that is vomiting could possibly have eaten something that is causing an obstruction and the vet needs to find the obstruction quickly before it's too late.
If the dog has diarrhea only and not vomiting remove the food for 24 hours. This allows the dog's system to reset and lessens the chance of vomiting or have diarrhea. Make sure that the dog is still drinking water you don't want the dog to dehydrate. Check frequently to make sure the gums are still nice and pink. Pale gums can be a sign of dehydration.
Give the dog food after 24 hours. If the dog still has diarrhea take it to the vet.
Professional Pet Sitting Services offered in the Upper to Mid-Pinellas County Area