In law, unring the bell is an analogy used to suggest the difficulty of forgetting information once it is known. When discussing jury trials, the phrase is sometimes used to describe the judge's instructions to the jury to ignore inadmissible evidence or statements they have heard. It may also be used if inadmissible evidence has been brought before a jury and the judge subsequently declares a mistrial.
Commenting on Court TV about the pre-trial release of nearly 200 pages of documents from a hearing on the sexual activities of the accuser in the Kobe Bryant sexual assault case, jury consultant Idgi D'Andrea said, "It's really hard to unring the bell, once that bell has been rung, and ask people to forget what they've heard."[1] In a more recent case, judge Reggie Walton said that he could not "unring the bell" when he declared a mistrial in the Roger Clemens perjury trial.[2]