If he is acting normally and is not lethargic, I would think it is not an emergency and you could try a few things at home.
If he was my dog, I would try to get his digestive system back to normal - it is obviously out of balance. That happens often when dogs eat something they shouldn't.
The first step is to fast him for 24 hours to give his intestines time to heal, provide always fresh water though.
Then start with a very bland diet (in water cooked lean chicken or other meat), small portions over the day. Ideal would be, if you could get hold of some Slippery Elm Bark powder and mix a teaspoon with warm Chamomile tea and offer this about half an hour before feeding. Dogs usually like it, if not you can add some honey. If the dog still refuses, it can be mixed with his food, but better is feeding it before. It basically coats the stomach and intestines and protects them.
If he is doing fine on this bland diet, you can start gradually mixing a bit of his regular food with the bland diet. Just a bit the first day, then a bit more the second day until eventually after about 1 week you can switch back to his normal food. If he is going backwards at any stage during this food change, go a bit slower.
All the best!
Dagmar