"The picture Kevin finds of 'Buzz's girlfriend' was a picture of a boy made up to look like a girl because Chris Columbus thought it would be too cruel to make fun of a girl like that. The boy that was used in the photo was the art director's son."
"In the scene where Harry attempts to bite off Kevin's finger, Joe Pesci actually bit Macaulay Culkin, leaving a scar on his finger."
"Joe Pesci deliberately avoided Macaulay Culkin on set because he wanted Culkin to think he was mean."
"Daniel Stern agreed to have the tarantula put on his face for exactly one take. He had to mime screaming because the noise would have scared the spider, and the scream was dubbed in later."
"The line "You guys give up, or are you thirsty for more?" was improvised."
"The concept for this movie originated during the filming of a scene in Uncle Buck in which Macaulay Culkin plays a character who interrogates a would-be-babysitter through a letterbox."
"The ornaments that Marv steps on are actually candy."
"The scene in which Kevin is buying a toothbrush was the first scene shot for the movie."
"Daniel Stern wore rubber feet for his barefoot scenes."
"Robert De Niro turned down the role of Harry."
"The role of Uncle Frank was written for Kelsey Grammer."
"Michael Douglas, Kevin Costner, Martin Sheen, Dan Aykroyd, Charles Grodin, John Travolta, Tom Skerritt, Bill Murray, James Belushi, Chevy Chase, Harrison Ford, Tom Hanks, Sean Penn, Mel Gibson, Sylvester Stallone, Christopher Lloyd, Rick Moranis, Dennis Quaid, and Jack Nicholson were considered for the role of Peter McCallister."
"Sigourney Weaver, Diane Keaton, Holly Hunter, Jodie Foster, Glenn Close, Geena Davis, Jamie Lee Curtis, Stockard Channing, Marilu Henner, Carrie Fisher, Kelly McGillis, Linda Hamilton, Helen Hunt, Laura Dern, Anjelica Huston, Sharon Stone, Michelle Pfeiffer, Bette Midler, Jessica Lange, Daryl Hannah, Debra Winger, and Annie Potts were all considered for the role of Katie McCallister."