When I was in the UK I used to breed and show dogs. Always made sure the dogs had access to all of the safe herbs in their garden. Funny to watch and see them sniff out the one's they felt they needed. I used to also feed them with pulped vegetables. They have to be pulped for the dog to be able to ingest them, otherwise they come out the same way they went in, lol. This is because in the wild they would get their "herbage' from the stomachs of their kills which was already part digested. mine also liked fruit and would steal it if they got the chance, each one liking a different fruit as their fave, but all liked apples. I know you shouldn't feed them grapes, you used to be able to but not now, think it must be insecticide or something.
Parsley is a good herb, look here
http://www.caninechronicle.com/Featu...nsey_1108.html