Censorship at the time meant that the subplot of Arrowsmith's liaison with another woman while still married meant that most of Myrna Loy's scenes were drastically cut. Although every attempt was made to restore the present version to its original length, there are still about 10 minutes missing.
John Ford later said of working with Ronald Colman in this film, "Arrowsmith was already cast when I went over to Goldwyn. Ronnie and I were friends, so I was delighted. Though he was the leading star of the business then, nobody ever acknowledged what a superb actor he was. They just accepted him as Ronald Colman. He did everything so easily. He never played drunken scenes or grew a beard or did any of those things which get Academy Awards, but he was the greatest actor I have ever known. [...] You didn't have to work with Ronnie - it was that simple. He knew exactly what to do and was letter-perfect when he did it."
The first American sound film to feature a Black character ("Dr. Oliver Marchand" played by Clarence Brooks) with a university degree who speaks perfect English, does not shuffle, and does not act in the usual stereotypical manner in which Blacks were depicted in Hollywood films at the time.
When he hired John Ford to direct, producer Samuel Goldwyn insisted that Ford lay off the booze for the duration of the shoot. Ford complied with this request, but shot the movie at an increased pace, eliminating scenes that he felt didn't add anything to the film. Helen Hayes was a little mystified when she discovered that some of her scenes weren't being shot.