You should make them compensate for the book, OP. Although, try not to be too harsh. I know if I threw up on a book, I definitely wouldn't have the guts to face the librarians wrath. FYL

Those patron need some sense knocked into them. Would they want a gift filled with vomit?

You would think that something like that would be self explanatory... People no longer speak up when things go wrong or not as expected. They just shove things aside and hope the next person to encounter the problem doesn't notice it... Like vomit in a book. No one will notice that.

That is just sick...

It must have been The Tale of Scrotie McBoogerballs

On the bright side they still return books, shame they're vomited on haha

some people are just disgusting and don't see what is clearly wrong with what they're doing. yuck. sorry OP hope you didn't get sick after that

There should be some sort of liability policy signed when a library card is received. Libraries don't always have the biggest budget for books.

Take the book back and then once they ask for another, take it and put some spaghetti in the back page. Then proceed to open the book to the final page, and smash it into their face; which then simultaneously spoils the ending and and gives them an pre dinner snack

I've never thought of reading to my dog...