The role of Professor Tinkle portrayed by Frankie Howerd was originally written for Kenneth Williams. He turned it down, as it clashed with filming for his TV show The Kenneth Williams Show (1970). Williams was then offered the cameo role of Walter Bagley, which he turned down as being too small, which was in the end cast with Charles Hawtrey.
Bernard Bresslaw learned all his native orders in a genuine African language - Fanagalo in South Africa, a.k.a. Chilapalapa or Chikabanga further North, the lingua franca of Southern Africa. But on the first day of shooting, the extras all stared at him dumbly - all were of Caribbean origin and thus completely confused by his orders. However Sidney James (born to a Jewish family in South Africa) claimed to recognize the real thing and congratulated him.
Terry Scott wasn't allowed to wear underwear under his loin cloth. In the scene by the river, his awkward posture as he lay next to Jacki Piper made his genitalia slip out during the long scene, making the camera crew and production staff corpse in the background. Scott's lack of underwear also caused trouble when he had to do vine swings, because he had to have metal pole equipment loop him from underneath and balance on it as he swung. He joked with Jacki that "[he] hoped [she] didn't want children after this movie".
The African Jungle scenes seen in the film were actually Pinewood Studios sets (albeit the use of any archive stock footage). Legend says that the jungle scenes were filmed in Kew Gardens, London. In fact, they were all filmed at Pinewood Studios, the same place all the "Carry On..." films were made.
This film was due to be entitled "Carry On Tarzan" but Peter Rogers was unable to get the rights to use the word Tarzan. Then they considered "Carry On Jungle Boy", which is what the movie was known as during the shoot, before eventually settling on the final title "Carry on Up the Jungle" after principal photography had finished.