Trivia: Arsenic and Old Lace

  • Actor Allusion:
    • The comments about Jonathan looking like Boris Karloff in the play—Boris Karloff originated the role on the stage.
    • In the movie, Mortimer leans against a tombstone with the name "Archibald Leach" (Cary Grant's real name).
    • The casting of Peter Lorre as a crazed German surgeon may be a callback to Mad Love.
  • Hey, It's That Guy!: Gooper Pollitt and Eddie Mars are the local cops. And Pop Corkle is their boss.
    • Look fast in the City Hall scene and you'll see Homer Bedloe as the news photographer pestering Mortimer. (Character actor Charles Lane was frequent bit player in Capra's films.)
  • Hey, It's That Voice!: You might not recognize Mr. Witherspoon's face, but you've probably heard Edward Everett Horton narrating "Fractured Fairy Tales" on Rocky and Bullwinkle.
  • Money, Dear Boy: InvertedCary Grant was so dissatisfied with his performance in this movie that he donated his entire salary from it to charity rather than profit from it at all. This was not the first time, either — in 1940, he donated his entire salary from The Philadelphia Story to the British war effort. For this film he donated it to the American effort.
  • What Could Have Been: Frank Capra originally wanted Bob Hope to play Mortimer in the film, but Hope was under contract with Paramount, who refused to loan him out. Jack Benny and Ronald Reagan were also considered for the role before they settled on Grant.