Jim Dale, Hattie Jacques, and Barbara Windsor in Carry on Again Doctor (1969)

Dr Nookey is disgraced and sent to a remote island hospital. He is given a secret slimming potion by a member of staff, Gladstone Screwer, and he flies back to England to fame and fortune. But others want to cash in on his good fortunes, and some just want him brought down a peg or two.