I have seen a lot of Star Trek fanart that shows Spock blushing with his cheeks flushed green. I'm aware that his half-Vulcan biology gives him copper-based, green tinted blood, so the coloring makes sense. But are there any canon sources on full-Vulcans (or Romulans, since they share common ancestry) having the physical ability to blush, and if they do, do their faces turn green in the same way human faces flush pink/red when we blush? Several people in the comments have pointed out that the average Vulcan wouldn't flush as it is an emotional response, what about body flushing, as a physiological response to illness or exertion?

potentially NSFW text below

In addition, are human and Vulcan's sexual response cycles similar enough that a Vulcan's skin would turn greener during sexual intercourse (ex: male Vulcans have green-tinted erections, Vulcans of various sexes getting a green-tinted sex flush across their chest)?

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    Blushing is a response to emotions, which full-Vulcans have suppressed. Ergo, full-Vulcans don't blush ;-)
    – Hans Olo
    Feb 24, 2020 at 10:28
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    There was an episode in ST: Enterprise where a group had rejected Surak's teachings, but they were very few in number; the vast majority of Vulcans have suppressed their emotions. However... since the Romulans are effectively Vulcans, perhaps the OP could/should include them in their question!?
    – Hans Olo
    Feb 24, 2020 at 15:44
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    Blushing might be an emotional response, but people can be flushed for other reasons, like after a lot of physical exertion, or being sick. Maybe the question should be reworded to reflect that?
    – Kai
    Feb 24, 2020 at 16:20
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    @Rebel-Scum According to Lt. Tuvoc Vulcan children live out their emotions untill they are old enough (early teens?) to learn how to controll/suppress them. Feb 24, 2020 at 21:17
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    This is all assuming that species other than humans even blush. Feb 26, 2020 at 14:03

1 Answer 1


Vulcan blood is green when oxygenated and rust colored when de-oxygenated (source). According to the same, this results in Vulcan skin taking on a greenish or brown hue to it, which is on display during the TOS episode Patterns of Force. When Kirk and Spock are being beaten by the Nazi Aliens, Spock is clearly greener than Kirk is, even in places where he isn't bleeding.

Having said that, some first season appearances of Spock do have him flushed and red faced, this isn't an emotion, and he's like that for the entire episode. (It may have been The Enemy Within I can't remember right now.) Regardless, it was an episode that was prior to the establishment of Spock's green blood, after which time the make up artists never put red on Leonard Nimoy again.

TL;DR: Yes, Vulcans ought to blush green, and TOS takes some steps towards demonstrating this once they came up with green blood.

Perhaps Picard will give us some blushing Romulans to settle this. As of right now, the episodes I've watched

Do not feature blushing Romulans.

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