I used to do it a bit when I trained dogs, mainly when a dog was a bit stale,eating alot of grass or off its tucker! I used to get tiny,tiny pills from the vet that you put under the eyelid or roll up little butter balls with a generous amount of salt in them and feed them one. Yes it seems a bit harsh at the time, but the dog feels alot better afterwards and I might of done it only 1-2 times a year!