According to TV Guide, "In October 1972 an account written by Leonard Greenwood appeared in the Los Angeles Times. It told of a Peruvian engineer whose son had been kidnapped by a band of Indians and of the man's successful search to locate the child. Screenwriter Rospo Pallenberg saw the news item and took it to producer-director John Boorman". The result was this movie.
Powers Boothe almost drowned during the shooting of one sequence where Charley Boorman was assisting Boothe cross a river. Boorman's pleas for assistance were initially interpreted by distant crew personnel as being part of his performance.
According to director Sir John Boorman's book "Money Into Light - The Emerald Forest: A Diary" (1985), Boorman's initial choice for the part of the son Tomme was C. Thomas Howell. When Howell was unavailable, John decided to use his own son Charley Boorman for the part.
The climate during the filming of the picture was regularly hot, humid, rainy and uncomfortable. Director Sir John Boorman has said that the wet inclement weather in Belém in Pará, Brazil was "a daily torrential downpour".
The film was "released with native language dialogue" and "became the first feature ever made for U.S. markets in a principal language other than English" according to the book "Picture This!: A Guide to Over 300 Environmentally, Socially, and Politically Relevant Films and Videos" (1992) by Sky Hiatt.