"Thou mayest well say that, Sancho," replied Don Quixote, "as thou sawest her in the full perfection of her beauty; for the enchantment does not go so far as to pervert thy vision or hide her loveliness from thee; against me alone and against my eyes is the strength of its venom directed.
There are no more uses of "venom" in the book.
Show samples from other sources
It was a cobra, whose venom could kill a person in minutes.
Paulo Coelho -- The Alchemist
I used elder python venom, straight from the depths of Tartarus.