Sick vet

A Vet was feeling ill and went to see her doctor. The doctor asked her all the usual questions, about symptoms, how long had they been occurring, etc., when she interrupted him

"Hey look, I'm a vet - I don't need to ask my patients these kinds of questions. I can tell what's wrong just by looking". She smugly added "Why can't you?"

The doctor nodded, stood back, looked her up and down, quickly wrote out a prescription, handed it to her and said "There you are. Of course, if that doesn't work,

Spoiler:

we'll have to have you put to sleep".