The Motion Picture Association of America originally refused to issue a seal for this movie because it shows drug addiction. The next year the production code was changed to allow movies to deal with drugs, kidnapping, abortion, and prostitution. The film was eventually assigned certificate #20011 in 1961.
This is one of the earliest examples of "stage" money that actually resembles the real thing being used, a situation which did not occur again in a prominent major film until Psycho (1960).
In a conversation with Robert Osborne, Frank Sinatra Jr. said the hands in the tight shots of Frankie's second dealing belong to Milton Berle.