The street that the St. Elmo bar is on is in the Universal back lot. Two or three buildings to the left is the Hill Valley Clock Tower from Back to the Future (1985).
Much like her character, Demi Moore (Jules) had a drug problem when she was cast in the film. One day, director Joel Schumacher actually demanded that she leave the set because she was really high. Moore had to go through rehab and promise to stay clean in order to play a character with a drug problem. Moore revealed in an auto-biography later that she had a cocaine problem and was using an eighth of an ounce of the drug every two days. She went to treatment for 15 days and then had a counselor with her while shooting the film.
The "booga-booga" cheer that the friends do when they are celebrating or just in a good mood was not originally in the script. In a later interview, Rob Lowe (Billy Hicks) stated that the cheer came out of observing fans whispering about the stars of the movie and then laughing. The cheer itself makes fun of what these whispered conversations sounded like from a few feet away.
St. Elmo's Bar is based on "The Tombs", a popular watering hole with Georgetown University students. For exterior shots, a full street set built at Universal Studios in Los Angeles was used.
Emilio Estevez (Kirby Keger) and Demi Moore (Jules) began dating during the filming of the movie. He said he was "deeply in love with her." For a time they were even engaged, though they never married.
Patrick Winningham: The brother of lead cast member Mare Winningham (Wendy Beamish) as a band member of 'The New Breed' Band.