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Memory Alpha
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Romulan corpse, 2371

A Romulan with blood on his face

Nanoprobes in action

Nanoprobes assimilating blood cells

Blood was a circulatory fluid present in the circulatory system of numerous lifeforms. Its primary function was to carry nutrients and respiratory gasses to cells and to remove waste products. Blood transfusions could only be undertaken between individuals with the same blood composition.

Many drugs needed to be introduced into the bloodstream to take effect. Anesthetic agents, for instance, were intravenously administered.

In 2004, a group of Xindi-Reptilians from the year 2153 began to synthesize a bioweapon to use against Humankind in the future. They employed the service of Loomis to abduct eight individuals of different blood types and bring them to a warehouse on Carpenter Street, where the Reptilians would extract blood samples and use them in producing the viral toxin to be used for their bio-weapon. (ENT: "Carpenter Street")

Lieutenant Malcolm Reed lost a bit of blood after he was shot with a projectile weapon and wounded in his left leg. (ENT: "Terra Nova")

In 2267, Rigelian scientists developed a drug that could accelerate the reproduction of blood. (TOS: "Journey to Babel")

In 2364, Doctor Beverly Crusher advised Captain Jean-Luc Picard how to use roots as a clotting agent for her bloody wound. (TNG: "The Arsenal of Freedom")

The Klingon spy J'Dan found a way to smuggle stolen information, encoded in amino acid sequences, in the bloodstream of an unknowing third person. (TNG: "The Drumhead")

When experimenting on crewmembers of the USS Enterprise-D, solanogen-based lifeforms slowly turned Lieutenant Edward Hagler's blood into a liquid polymer, thereby killing the officer. (TNG: "Schisms")

In 2369, when trapped in an illusory scenario of being in the Tilonus Institute for Mental Disorders, Commander William T. Riker encountered a guard who told him the supposed scenario of how he had entered the institution. The guard stated that there was blood all over Riker's hands and clothes, from him having stabbed a man. (TNG: "Frame of Mind")

Some species did not have blood at all, like the humanoid Breen. (DS9: "In Purgatory's Shadow")

Klingons swore blood oaths as a promise of vengeance, to sanctify various alliances, and as vows by the shedding or mixing of blood. (DS9: "Blood Oath")

T'Pol had Vulcan K-cells in her blood. These cells stopped her from being infected with a mutagenic virus on the Loque'eque homeworld in 2153. (ENT: "Extinction")

Both Spock and Sarek had type T-negative blood, which was a rare Vulcan type. (TOS: "Journey to Babel")

As late as 2267, blood was taken with a needle for medical tests. (TOS: "The Deadly Years")

Julian Bashir had type B-negative blood. (DS9: "In Purgatory's Shadow")

Odo had type O-negative when he was a humanoid for a short time. (DS9: "Broken Link")

Solbor's blood revealed the text of the Book of the Kosst Amojan. (DS9: "The Changing Face of Evil")

Blood chemistry[]

Blood chemistry is a term used to describe the composition of elements, chemicals, and other substances in an individual's blood. The chemistry of the metal-protein complex of the component cells responsible for respiratory delivery influence the color of the blood.

Known colors and chemical compositions included:

Furthermore, in ST: "The Trouble with Edward", tribble blood is described as "blood red".

Tuvok's blood boiling

Green Vulcan blood

Bolian blood

A sample of Bolian blood

Klingon blood in zero gravity

Pink Klingon blood in zero gravity

Na'kuhl blood

Yellowish Na'kuhl blood

Species 8472 blood

Blood of Species 8472

Xahean orange blood

Orange Xahean blood

It is not known what color blood Gosis' people had, only that it was not red. Its chemical composition was also unknown, though it was not iron-based. (ENT: "The Communicator")

Rigelians were known to share a similar blood chemistry to that of Vulcans. (TOS: "Journey to Babel")

The chemistry of Acamarian blood oddly had an iron and copper-based composition. (TNG: "The Vengeance Factor")

Bolians had a blood chemistry very different from that of other species, especially Vulcans. If a blood transfusion was given from a Vulcan to a Bolian, it would result in the death of the Bolian. There were instances when artificial blood was unavailable and existing blood cells were genetically altered for inter-species transfusions to be successful. (VOY: "Prototype")

In 2367, Dr. Beverly Crusher noticed that Lieutenant Commander Susanna Leijten's blood chemistry was slightly off after beaming back from the surface of Tarchannen III. It was later discovered that she was in fact being transformed into another lifeform. (TNG: "Identity Crisis")

When creating the Jem'Hadar, the Founders deliberately omitted a key isogenic enzyme from their blood chemistry, giving it to them in the form of ketracel-white. The Jem'Hadar needed to keep taking the white or they would die, thus ensuring their loyalty to the Founders. (DS9: "The Abandoned")

In 2371, the USS Voyager's EMH, The Doctor, discovered that Ensign Seska's blood chemistry was not consistent with that of a Bajoran. Her cover story was that she suffered from Orkett's disease as a child during the Occupation of Bajor, and that she had received a bone marrow transplant from a Cardassian woman named Kattell. (VOY: "State of Flux")

After the Borg transplanted skin onto Data's arm and the Borg Queen activated his emotion chip, he felt pain when a Borg drone cut this flesh and blood ran out of it. (Star Trek: First Contact)

Rather then simple blood, Xaheans had blood-based circulatory fluid. (ST: "Runaway")

See also[]


Background information[]

In Star Trek VI: The Undiscovered Country, Klingon blood was portrayed as pink and lavender, while in Star Trek: The Next Generation and Star Trek: Deep Space Nine it was red. The supposed reason for this is that having floating red blood all over the ship was considered too violent, and would have given the movie a more extreme rating than would be appropriate for the target audience. Pink blood makes it obvious at a glance that the violence is simulated, not real. Pink blood appears to have made a reappearance in Star Trek: Discovery, as it was seen in "Point of Light". See here for a more detailed discussion of Klingon blood color.

Brown blood – present in Cardassians – is only found in real life in the mollusc Pinna squamosa, which is similar to hemocyanin, but is based on manganese, instead of copper. Violet blood – present in Klingons – is found on certain molluscs, which is based on iron, but in a non-heme protein.

Unused scripted references[]

In the second revised final draft script of TOS: "The Corbomite Maneuver" (dated 20 May 1966), Sulu light-heartedly declared, "I don't have a drop of Western blood."

The final draft script of TOS: "Miri" included an ultimately unused line in which Kirk said to the Onlies, "Blood. My blood. Are you afraid of it? Most people are...."

In the writers' first draft script of ENT: "Dear Doctor", the sight of blood, while Doctor Phlox was bandaging a laceration on Trip Tucker's hand, caused a large, tough-looking engineering officer standing nearby to suddenly faint, so Phlox then switched his focus to the felled giant.


Several non-canon sources have suggested that the bases of blue-blooded aliens' blood are silicon and cobalt. (citation needededit) This would be logical, as some creatures in reality have blue blood based on molecules other than iron and copper.

External links[]