The scene where Tessa (Rachel Weisz) walks through the slum, numerous children ask her "How are you?" and she responds "I'm fine, how are you?" was unscripted. The children are actual children who live in Kibera and not extras.
The character Tessa Quayle was based on famous social activist and charity worker Yvette Pierpaoli, who was killed in 1999 with two other social workers when their truck crashed in Albania. The book was written in her memory.
After filming, the Constant Gardener Trust was set-up to help the inhabitants of the slums near Nairobi where the crew had been filming. The Wikipedia website states: "The poverty so affected the film crew that they established the Constant Gardener Trust to provide basic education to those areas (John le Carré is a patron of the charity)."
The filmmakers installed water tanks, a new bridge and a classroom in Kibera, the slum in which the film was shot. They also built a secondary school in the desert of northern Kenya where the final scenes were photographed.
Marcus Lorbeer (played by Pete Postlethwaite) wears a baseball cap that has a yellow equal sign (=) inside a blue square. This is the logo of Human Rights Campaign, a non-profit organization that lobbies for equal rights based upon sexual orientation and gender identity. It is the largest gay, lesbian, bisexual, and transgender advocacy organization in the United States.
Danish actress Iben Hjejle was originally cast as the German woman Birgit and was signed on. When the film's German financiers discovered that a Dane had been cast as a German, they made sure a German actress, Anneke Kim Sarnau, was cast instead.
First of two filmed adaptations of John le Carré novels to have a score composed by Alberto Iglesias. His second was for Tinker Tailor Soldier Spy (2011). Both music scores were Oscar nominated in the Best Music Score category, for the Academy Award for Best Achievement in Music Written for Motion Pictures, Original Score.
Producer Simon Channing Williams bought the rights of the book in advance before its release in 2001 with the intention of bringing it to screen. In order to get John le Carré's permission to do so, he wrote a letter to Le Carre's attorney Michael Rudell informing him of the intention and flew to New York on the same day. This is the second time that Le Carre has worked on the screenplay of a film; the first was The Tailor of Panama (2001). To ensure total accuracy, Nairobi-based molecular biologist Bonnie Dunbar was brought in as the film's consultant.
The synopsis of this movie's source novel "The Constant Gardener" (2001) by John le Carré on his personal website reads: "Tessa Quayle has been horribly murdered on the shores of Lake Turkana in Northern Kenya, the birthplace of mankind. Her putative African lover, a doctor with one of the aid agencies, has disappeared. Her husband, Justin, a career diplomat and amateur gardener at the British High Commission in Nairobi, sets out on a personal odyssey in pursuit of the killers and their motive. His quest takes him to the Foreign Office in London, across Europe and Canada and back to Africa, to the very spot where Tessa died."
Actress Naomie Harris, who plays Miss Eve Moneypenny in the James Bond films, became the sixth major actor who has starred in motion pictures based on works of both John le Carré and 'Ian Fleming (I)', both famous spy novelists. Harris' role as Gail Perkins in Our Kind of Traitor (2016) follows her two previous appearances in Bond movies, in Skyfall (2012) and Spectre (2015). Pierce Brosnan and Sean Connery are actors who have both previously portrayed James Bond on screen and both have starred in le Carré filmed adaptations, they being The Tailor of Panama (2001) and The Russia House (1990) respectively, the latter which has a title that evokes Fleming's From Russia with Love (1963) which starred Connery as Bond. Of Connery's 007 Bond films, his one unofficial Bond movie, Never Say Never Again (1983), co-starred Klaus Maria Brandauer, who also appeared in The Russia House (1990). Alas, Connery and Brandauer have starred in the same two Bond and le Carré spy movies. Moreover, Harris and Brosnan both appeared in the thriller adventure cinema movie After the Sunset (2004). The first actor to portray an M character in the Bond films, Bernard Lee, was the first actor ever to do both Bond and le Carré. Lee appeared as Patmore in le Carré's classic spy movie The Spy Who Came in from the Cold (1965), which was the first ever filmed adaptation of a le Carré novel. The le Carré adaptation film The Constant Gardener (2005) starred Ralph Fiennes, who played Justin Quayle, and has portrayed the Bond series' new M character Gareth Mallory in both Skyfall (2012) and Spectre (2015), as has Harris played Eve Moneypenny in the two. Rachel Weisz, the wife of James Bond actor Daniel Craig, previously starred as Tessa Quayle in The Constant Gardener (2005), for which she won a Best Supporting Actress Academy Award, with Wiesz and Fiennes playing husband and wife in that movie.
Source author John le Carré included 'The Constant Gardener' as one of his four best novels during an interview on 5 October 2008 on BBC Four. The other best works he selected were 'Tinker, Tailor, Soldier, Spy', 'The Tailor of Panama', and 'The Spy Who Came in from the Cold'.
This motion picture's closing credits dedication states: "This film is dedicated to Yvette Pierpaoli and all other aid workers who lived and died giving a damn". In his original source novel "The Constant Gardener", author John le Carré also wrote a dedication at the end of the book.
This feature film's epilogue written by John le Carré during the closing credits reads: "Nobody in this story, and no outfit or corporation, thank God, is based upon an actual person or outfit in the real world, but I can tell you this, as my journey through the pharmaceutical jungle progressed, I came to realize that, by comparison with the reality, my story was as tame as a holiday postcard - John le Carré." In his original source novel "The Constant Gardner", author John le Carré also wrote an afterword at the end of the book.
The trivia items below may give away important plot points.
At the eulogy for Justin, Pellegrin quotes this line: "Nothing in his life became him like the leaving it." That quote is taken from the beginning of Macbeth: [King Duncan: Is execution done on Cawdor? Are not those in commission yet return'd? Malcolm: My liege, they are not yet come back. But I have spoke With one that saw him die; who did report That very frankly he confessed his treasons, Implor'd your Highness' pardon, and set forth A deep repentance. Nothing in his life Became him like the leaving it.] In Macbeth, the "him" referred to is a traitor who had been executed for betraying his king. Justin has been murdered for doing the same thing. Pellegrin's gall in using this quote is amazing, especially when it seems fairly clear he ordered the hit in the first place.
In a deleted scene, seen on DVD extras, Swedish actress Pernilla August plays an employee at the Canadian company that was responsible for the drug research. Her character gave Justin Quayle information that led him to Dr. Lorbeer. Moments after doing this, she is killed in a mysterious hit-and-run car accident.