"Something's rotten in the state of Denmark" is one of the most recognizable, most quoted lines from Shakespeare. Marcellus used this line when speaking to Horatio in Shakespeare's play, Hamlet in Act 1, Scene 4. During the scene, Horatio and Marcellus try to keep Hamlet from following the ghost of his (Hamlet's) father because they are afraid it might be something evil disguised as Hamlet's father. Hamlet, however, follows the ghost. Marcellus is unhappy and more than a bit angry that Claudius has politically mismanaged Denmark, which is now filled with corruption, both politically and morally." This is what he means when he says, "Something's rotten in the state of Denmark." Something is terribly wrong.The words are used to describe corruption or a time or situation in which something goes terribly awry.