The Boulugres.

Herbert, a Candide-like idealistic teenager, wants to become a doctor to help humanity, but his parents insist that he become a rich aviator. Herbert runs away to study medicine with a wise old Boulugre, and vows to help the natives of undeveloped countries. He finds that the Boulugres are a tribe whose men have a disgusting mushroom growing from their heads. He develops a vaccine for them, wants to give it to them free, and fights with Chousk, a pharmaceutical tycoon who wants to sell it to them. But the Boulugres are deathly afraid of needles and refuse to be inoculated by anyone. Herbert, disillusioned, escapes into love with a Yugoslav airline stewardess.