Jim Dale was disgruntled with the part he had been given and turned down the role of the Jungle Boy because of its dialogue limitations of just grunts and groans gibberish. The character in the end was cast with Terry Scott instead.
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.
The film's joke alternate titles seen at the start of the opening credits were "the African Queens", "Stop Beating About the Bush" and "Show Me Your Waterhole and I'll Show You Mine". Joke alternate titles that were dropped and weren't used at the beginning of the movie included "The Lust Continent" and "Don't Shoot 'til you See the Whites of their Thighs".
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.