Production went a day over schedule due to the intricate camera setups used by director Harvey Hart, which had good results but were too time-consuming. Hart also made things difficult for the editors by "camera cutting" the show, leaving few choices of shot available. Due to these factors, Hart was not invited back to the show.
A lengthy monologue in which Harry Mudd attempted to persuade Uhura into taking the Venus drug was also excluded from the episode because it was deemed too wordy and long. Roger C. Carmel was extremely disappointed by the deletion of this monologue, later describing it as "wonderful". He explained, "I remember being very disappointed because I felt the monologue was very effective and very much to the point of the show's philosophy." He nevertheless liked this episode, just as much as he liked Star Trek: I, Mudd (1967).
This is the first episode in which the Enterprise's power source is named, however, they are called simply "lithium crystals", and not "dilithium" as was done in all later episodes of this and all later incarnations of Star Trek. This and Star Trek: Where No Man Has Gone Before (1966) are the only episodes that do so.
This episode contains one of a few times in the series where Spock's nationality is called "Vulcanian" rather than simply "Vulcan". Mudd says to Spock, "You're part Vulcanian, aren't you?" Mudd was somehow able to distinguish this in Spock, apparently on sight. It is possible that, in the early days of TOS, Spock was meant to look more Human than most full-blooded "Vulcanians," which would explain Mudd's ability to recognize his hybrid status on sight. In later episodes, and throughout the films and later series, Spock is considered to look like any full-blooded Vulcan. It is also possible that the episode's writers meant the viewer to conclude that Mudd had some pre-existing familiarity with both Spock's heritage and his inclusion in the Enterprise's command crew.
Gerald Perry Finnerman was encouraged to be creative in choosing dramatic lighting and camera angles. Robert H. Justman recalled that he said to Finnerman, "We're all in outer space, Jerry, and we're in colour. NBC claims to be the first full-colour network, so let's prove it for them. When you light the sets, throw wild colours in - magenta, red, green, any colour you can find - especially behind the actors when they're in a close shot. Be dramatic. In fact, go overboard. Backlight the women and make them more beautiful. Take some chances. Nobody can tell you that's not the way the future will look. How can they? They ain't been there yet." Bob Justman was very pleased with the final results in this episode. He stated, "Guest stars Karen Steele, Maggie Thrett and Susan Denberg, good-looking in real life, looked even more radiantly lovely and ravishing as they worked their magic upon Captain Kirk and crew - after Jerry worked his magic upon the three actresses."
NBC Program Manager Jerry Stanley recalled that "One of the problems we had was in trying to talk [Roddenberry] out of some of his sexual fantasies that would come to life in the scripts. Some of the scenes he would describe were totally unacceptable". William Shatner noted "that NBC allowed "Mudd's Women" to be produced at all is still a minor miracle".
Part way through the episode, the ship depletes their lithium supply and is running on battery back-up. During the external shots following the Warp Nacelles are dark, since they are not capable of operating. When the ship arrives at Rigel 7, the Warp Nacelles are once again glowing, yet they have not received any Lithium.
Teleplay writer Stephen Kandel recalled of this episode, "Gene had the idea of using a personal enhancer-allure drug, and I provided the character [of Harry Mudd]. We spent an afternoon talking about it, and out of the conversation evolved the story idea and then, of course, I wrote the story. Gene went over it in great, meticulous and obsessive detail, and then I wrote the script."
The velour uniforms used in this episode had shrunk since they were first used in Star Trek: The Corbomite Maneuver (1966). According to Robert H. Justman and Herbert F. Solow's book Inside Star Trek: The Real Story, the velour uniforms shrank every time they were cleaned. The actors' union requirements specified that the costumes had to be cleaned daily.
Although Karen Steele and Maggie Thrett were given makeup and facial appliances (primarily rubber cement was applied, to make the skin appear 'wrinkled') to make them appear 'ugly' as the Venus drug wore off in Harry Mudd's quarters, Susan Denberg appears not to have been to a lesser extant, simply, by having her hair was uncombed and unstyled, and no eye makeup (eye liner, eye lashes, shadow). It might sound 'sexist'; a woman 'must' be 'made up', but, it is what it is, and by simply not doing these things - to any woman - even those who appear 'natural', their appearance can be much different.
The origins of this story can be found in Gene Roddenberry's early 1964 series outline, Star Trek (1966) is..., as a story proposal entitled "The Women". That synopsis reads, "Duplicating a page from the 'Old West'; hanky-panky aboard with a cargo of women destined for a far-off colony."
Kirk's quarters have a window in this episode and a few others to follow. These may not be his normal quarters because Spock directs the turbolift to take him, Mudd and the women to Deck 12. The window will disappear in subsequent episodes. Kirk's quarters are later situated on Deck 5.
This and Star Trek: Where No Man Has Gone Before (1966) are the only episodes where the crystals that power the Enterprise's engines are called "lithium". Throughout the rest of the series, the crystals are called "dilithium."
This episode's final scene aboard the bridge is the series' first suggestion that Vulcans have a different arrangement of internal organs than Humans. Specifically, McCoy places the Vulcan heart at roughly the place of the Human spleen. This is later made more explicit in Star Trek: The Omega Glory (1968).
Upon its initial airing, this episode was generally well received. Stephen Kandel. Roger C. Carmel likewise said about the episode, "It was a pretty big success and they got a lot of positive reaction from it."
Regarding the script, Herbert F. Solow commented, "It was very well written, it was fun, and it featured three beautiful women-hookers selling their bodies throughout the galaxy. It later became a standout and much-loved episode in the series."
Harlan Ellison visited the set during the filming of this episode. Ellison was writing his first draft teleplay for Star Trek: The City on the Edge of Forever (1967) at the time in an office at the Desilu lot. Associate producer John D.F. Black couldn't find Ellison in his office and was angered when he finally found him on Stage 10, posing for photographs and eating lunch with the cast and crew.
At one point, Scotty refers to the Enterprise as weighing "almost a million gross tons" in observing the tenuousness of "...almost a million gross tons (of starship) depending on a crystal the size of my fist...". In the Star Trek Star Fleet Technical Manual, author Franz Joseph establishes the weight of a Constitution-class starship as 190,000 tons - just as Gene Roddenberry did in his very first proposal for the series, Star Trek is....
This marks the first appearance of the sound stage cyclorama used for different planets throughout the series, which was lighted with different coloured filters, to give an appearance of many unique-coloured atmospheres. Associate producer Robert H. Justman came up with this idea after realizing that reusing the same cloudy background from the two pilots, over and over again, would result in all planets looking the same. Justman personally decided the backdrop colours for each episode. Problems often arise when the colored gels either faded or burned up after a short while in front of a hot light, and the burning gels made an unbearable odour on the set. The backdrop lighting used in this episode for Rigel XII, with tornadic streaks in it, was also utilized in Star Trek: The Enemy Within (1966).