Contrary to Technicolor's edict, Warners shot a black-and-white version of "Doctor X." At least two scenes in the black-and-white version use different takes than the color one: the scene with Lee Tracy and Mae Busch in the house of prostitution scene and the sequence with Tracy in the skeleton room.
For a time Warner Brothers did not have a print of the original Technicolor version and it was assumed to be lost. The Technicolor version was finally discovered and restored by the UCLA Archives.
The New York waterfront sequences were shot on the still standing Twinkletoes set left over from the 1926 Colleen Moore vehicle, in which in stood in for London's Limehouse District.
The play opened in New York City, New York, USA on 9 February 1931 and had 80 performances.
This is the film for which Michael Curtiz is quoted as saying, "This will make your blood curl!"
Warner Bros. paid $5,000 for the rights to the play.