some kind of chemical that tasted really bad to dogs and cats

And I think we should call it "Vet's Surgery(tm)" and we'll all become millionaires if we can somehow bottle it. I don't know what it is about those places but dogs/cats are certainly allergic to them. Perhaps they have a 6th sense and can read their owners minds on the way in when we say to ourselves "I just know this is going to be expensive"!