I meant to add it would be best to not feed the dog but make sure it has and is drinking fluids.
If this is continuing, you definitely need to get your dog into the Vet. This could be causes by any number of things and a Vet needs to determine the cause.
Yes you do! If this is a puppy (And been going on more than 24 hrs.), then you may have an emergency on your hands....Dehydration from the vomiting & no fluid intake can be fatal, quickly....Please, get him to a Vet ASAP...Let us know what happens & good luck...Karla