My friend's dog has been throwing up yellow foamy stuff about twice a week. We live in the desert so there really isn't any grass around and she's stopped giving her some of the treats, but still today was another mess. Any help, before going to the vet?

check his diet, did he change foods reccently? some breeds are allergic to certain things, they may have had onions by accident, wich dogs arent suppose to have

You should take the dog to the vet. She seems to be getting into something that is poisonous to her - you just should be on the safe side and if you can bring in a sample of what the dog is throwing up they can analyze it. At least call the vet and tell them about this and see what they say.

Yellow foamy stuff is often an indication the dog isn't throwing anything up but his own bile.

Is this dog eating?? You need to check it's eating habits. Dogs sometimes get an upset stomach, and vomit, and it's nothing to worry about, but if this is a prolonged deal, you should probably seek proper medical attention.