question on British slang

Of the four mini-movies in this series, "Taming of the Shrew" is our favorite. I have a question about the phrase Petruchio uses when first talking to Harry - "Have you eaten a cockroach?"

I tried looking this expression up but I can't find anything. I had thought it meant "Are you hungover?" but from Harry's reply, "...not recently" I am guessing it might mean something else?

Thanks!