When you say milk, do you mean breastmilk? Breastmilk is considered a "clear liquid" and if your baby will take that, then s/he will OK without pedialyte or other liquids. Don't give soft drinks. Water. Juice. Pedialyte. Might need to cut the pediatlyte with water to help it stay down.
When we all had a horrible stomach bug a few years ago, we were told to hold 1 teaspoon of crushed ice in our mouths. It will be absorbed through the skin of the mouth and not need to hit the stomach (where it would get returned). Started off slow, like once every hour or half hour. See if you can do similar for your baby (a baby spoonful).
I do agree, though, that if baby can take milk and keep any of it down, that's better than a kid who can't take anything.