Warner Independent Pictures and The Yari Film Group brought in a Chinese production company to help finance this movie. The Chinese partner was granted approvals over the script and the finished movie. It was concerned about this movie's depiction of the uprising during the Chinese Revolution, and the cholera victims, and asked for these scenes to be reduced. Producer/star Edward Norton and Executive Producer/Director John Curran disagreed. In the end, about thirty-eight seconds of footage was removed.
Liev Schreiber said in an interview that Naomi Watts "forced them to hire me" for this movie. "She wanted to continue our relationship, and the only way to do that was to take me on the road with her."
Producer and star Edward Norton injured his back during filming, breaking three vertebrae, when his horse threw him onto some rocks. He has said in interviews that he did not seek proper medical treatment until he had finished filming and had returned to Hong Kong.
Because the film was shot very much out of chronological order, John Curran asked Naomi Watts and Edward Norton to give a wide range of performance in their scenes; some takes of the same scene were performed with subtlety, others were bigger and more emotional. This allowed Curran to find continuity in the editing process.