In one scene where the Colonel is seen placing bets with the medical orderly, Wilfrid Hyde-White changed the name of the horse from the scripted "Bloody Mary" to "Rambler", which Hyde-White had backed earlier in the day. Harry Locke visibly reacts to the name change, but doesn't spoil the take.
"Carry On" regular actor Bernard Bresslaw was not cast in this film, but his legs and feet did make an appearance during the scene where Ted York (Terence Longdon) is having a bath being bathed by Joan Sims. The legs of Longdon were thought to be too thin, so Bresslaw acted as a body double for them.
Kenneth Williams kept falling asleep, due to the combination of warm studio lights and acting on a bed. When Gerald Thomas would wake him up, Kenny would swear blind that he wasn't asleep. So the next time it happened, Thomas put a sign around his neck, and took a photograph. When Kenny tried to wriggle his way out of it again with protestations of not being asleep, Gerald showed him the photograph - apparently Kenny's language became very colourful.
This is the most successful Carry On film of all time in the US. It was even shown in cinemas three years after its official release and led to Norman Hudis to leave for Hollywood to write many of their successful movies.
When the film was released, Wilfrid Hyde-White's agent threatened to sue, on the grounds that the backside used in the daffodil gag belonged to someone other than his client. The action was dropped when it was revealed that the whole thing was done by suggestion, and that no backside is seen.
Originally there was a joke in the film concerning the lead weights holding Bill Owen's leg in the air. When the tag line was "Pick up Mr Hickson's Ball's" was put before the censors, they thought it to much.
When the film became as big a hit as Carry On Sergeant (1958), Peter Rogers announced that the next four films would be Carry On films. He decided to offer the Carry On team a percentage of the takings, as opposed to a fee, but they declined. Years later, whenever anyone complained about the money, he just reminded them of this fact.
When Hinton is seen crying with his headphones on, a comment is made about him listening to 'Mrs Dale's Diary'. 'Mrs Dale's Diary' was a BBC radio serial which ran from 1948 to 1969. It was broadcast daily and was very popular.
Some of the film's literal English language translations of its foreign language titles were "40 Degrees of Love" (Belgium, South America), "41 Degrees of Love" (Germany), "Isn't It Wonderful Doctor" (Denmark), "Nurse Does All The Work" (Greece) and "Laughing Gas & Beautiful Girls" (Finland).
Wilfrid Hyde-White, living in America at the time, agreed to play the Colonel without reading the script and getting paid to return to England so allowing him to attend the Grand National Horse race. A picture of a horse is seen on the bedside locker cupboard next to him during scenes.
The film was based on the play Ring for Catty by Patrick Cargill and Jack Beale.. When the rights were bought in 1956 it was then shelved for over a year until Richard Attenborough and the Boulting Brothers expressed interest in it. Sydney Box then paid a further £1,000 to secure the rights and Peter Rogers registered the original title along with two others including Carry on Nurse.