main image kree-breathing_potion


Classification: Extraterrestrial (Kree) medical technology

Creators: Kree medical specialists whose identities have not been revealed.

User/Dispensers: Medic Una (deceased), Medic Eine

User/Recipients: Captain Mar-Vell (deceased), Captain Tar-Rell

Aliases: None

First Appearance: Marvel Super-Heroes II#12 (December, 1967)

Powers/Abilities/Functions: The breathing potion is able to alter the bodies of members of the Kree species to enable them to breathe in atmospheres that are different enough from that of their homeworld, Hala, that Kree would be unable to breathe normally in them.

Limitations: The breathing potion can only enable Kree to breathe in un-Hala-like atmospheres for sixty Earth minutes at a time. There is no known way in which this time limit can be exceeded. It must be presumed that simply taking a larger dosage does not extend that time limit.


   In its pure form, the breathing potion is too concentrated to drink and must be diluted with water to be safe to use. Whatever harmful effects there might be to drinking pure breathing potion have not been revealed.

(Marvel Super-Heroes II#12) - As the Kree starship Helion approached the planet Earth, its commander, Colonel Yon-Rogg, ordered Captain Mar-Vell to get into his battle suit and to prepare for landing, stating that Medic Una would administer the breathing potion to him. Puzzled, Medic Una asked, "Only to Captain Mar-Vell, sir?? What about the rest of the landing party?" Mar-Vell then revealed to her that there would be no landing party because the colonel had ordered him to carry out the mission alone. When Una protested that it was against all standard practice, Mar-Vell urged her to be quiet, and the two of them whispered about how Yon-Rogg was trying to get Mar-Vell killed so that he could have (he thought) Una for himself. After ordering them to stop whispering in his presence, Colonel Yon-Rogg ordered Medic Una to have Captain Mar-Vell drink the breathing potion with no further delay as they were about to land. As Mar-Vell drank the potion, Yon-Rogg reminded him that, if he were forced to remove his protective helmet, that potion would allow him to breathe for sixty Earth minutes.

   Hidden by its Aura of Negativism, the Kree starship landed on Earth where Mar-Vell used his air-jet belt to exit the ship. Standing upon Earth, Mar-Vell thought to himself about how, when not wearing his protective helmet and battle suit, his strength would decrease in exact proportion to the time he was exposed to Earth's atmosphere. After some mishaps, Mar-Vell put on the simulated Earth clothes he had brought with him, encountered a truck driver who was willing to give a hitch-hiker a lift to the next town, and used the American currency that he had been given to rent a room in a hotel where he signed in as "C. Marvel." As soon as Mar-Vell was in his room, Yon-Rogg had a wrist monitor transferred to his wrist, and seconds later Mar-Vell received a signal from the Imperial Minister on the home planet itself. Once the brief message had ended, the breathing potion ran out and Mar-Vell, unable to breathe, had to put on his helmet.

(Marvel Super-Heroes II#13) - After modifying his Universal Beam hand-gun into a Uni-Beam wrist-blaster, Mar-Vell realized that he had only one capsule of breathing potion left. He took the capsule, contacted the starship so that he could obtain a fresh supply, and then left in the middle of the night, arousing the curiosity of the hotel's nosy night clerk. When, after walking some distance out of town, the sensors in his wrist monitor detected the approach of the starship, Mar-Vell donned his helmet and battle suit so that he could fly up to them. However, as Mar-Vell approached, Yon-Rogg planned to "accidentally" activate the starship's laser. Una realized what he was planning so Yon-Rogg had her removed and confined to her quarters. When Mar-Vell was less than an Earthly mile away, Yon-Rogg fired the destruct-laser but the beam struck a small private plane that had flown between the starship and Mar-Vell just as Yon-Rogg fired. Seeing that Mar-Vell had only been momentarily stunned, Yon-Rogg ordered the ship to return to orbit, leaving Mar-Vell to die, after realizing that he could avoid being blamed if he claimed that the incident had jeopardized the ship. Left on Earth, Mar-Vell investigated the wreckage and found the dead body of the pilot, Dr. Walter Lawson, an expert on missile guidance systems who had been heading to the nearby base, the so-called Cape. Mar-Vell took his identification papers so that he could alter them slightly in order to gain entrance to the base. However, having taken the last of his breathing potion, Mar-Vell could survive less than an hour without his life-giving helmet.

   Fortunately for Mar-Vell, his beloved Una was very resourceful. Realizing why Mar-Vell must have been returning to the starship, Una took advantage of the fact that Yon-Rogg had had her confined to her quarters to use materials she had there to create some more of the vital breathing potion. She then released some sleep-inducing Morpheo-gas into the ship's ventilation system, putting the rest of the crew to sleep long enough for her to use the transferral machine to beam the potion to Mar-Vell wherever he was. Having returned to his hotel room so that he could don his helmet in secret, Mar-Vell witnessed the capsule of breathing potion appear and knew that Una had sent it.

(Marvel Super-Heroes II#13) - The following morning, Mar-Vell went to the Cape where he used his altered credentials to pass himself off as Dr. Walter Lawson. Mar-Vell spent the next seven days working there, during which time "Lawson" took a coffee break once every hour so that Mar-Vell could secretly drink a dose of the liquid potion.

   On the seventh day, "Dr. Lawson" first met the commander of the Cape, General Bridges, who escorted him to a reinforced and heavily-guarded hangar where the military were secretly holding the inert form of Intergalactic Sentry #459, which the Kree had believed had been destroyed by the Fantastic Four. "Lawson" also first met the missile base's head of security, Carol Danvers, at this time. Yon-Rogg also learned of the Sentry's survival and planned to use it to kill Mar-Vell.

(Marvel Super-Heroes II#13 / Captain Marvel I#2 (fb) - BTS) - That night, Yon-Rogg remotely repowered the Sentry whose programming to defend itself caused it to decide that it had to destroy the base. General Bridges ordered some Air Force jets to the base and then called the only hotel in town to speak with "Lawson." Although it had been nearly an hour since his last dosage of the breathing potion, Mar-Vell, after being told that the robot had come alive and was on a rampage, knew that he would be wearing his battle-helmet when he went to stop the Sentry so he didn't bother to drink any breathing potion at that time.

kree-breathing_potion3 kree-breathing_potion4

(Captain Marvel I#1 - BTS / Captain Marvel I#2 (fb) - BTS) - During Mar-Vell's battle with Sentry #459, the hour's worth of coverage provided by his most recent dose of breathing potion ran out. However, since he was wearing his helmet, Mar-Vell was unaffected and didn't even realize what had happened.

(Captain Marvel I#2) - Later still that night, after ending the menace of Sentry #459, "Captain Marvel" flew off and secretly returned to his hotel room where he removed his battle helmet. However, his relief was short-lived when he immediately discovered that he could hardly breathe. Remembering that his most recent dose of the breathing potion had been about to run out when he had received the phone call from General Bridges, Mar-Vell knew that he needed more of the potion because his life-giving battle helmet needed a chance to recharge after the strain of battle. Since the breathing potion was too concentrated to take in its pure form, Mar-Vell, while still wearing his Kree uniform, was forced to sneak down the hallway to the hotel's bathroom where he was able to dilute the potion with tap water to create a dose that he then took so that he could breathe on Earth for another hour. A few minutes later, Mar-Vell discovered that the carry-all cylinder he had hidden under his bed had been stolen and, knowing that any tampering would have activated a timing device that would set off the miniature nuclear bomb inside in two hours, he set off to find it. Soon deducing that the night clerk had stolen it and was probably headed to the base, Mar-Vell also headed there but encountered the Super-Skrull, who had been tracking the Kree carry-all cylinder. Their battle carried them within the base where the Super-Skrull defeated Captain Marvel and flew away with him, leaving the activated cylinder behind.

(Captain Marvel I#3) - Later still that night, the Super-Skrull took his defeated foe, who was pretending to be unconscious because he was too weak to fight, to his nearby hidden spacecraft to interrogate him as to why he was on Earth. After securing him to a table, the Super-Skrull removed Mar-Vell's helmet, causing the Kree warrior to wonder if he would die by atomic blast (when his stolen carry-all cylinder exploded) or by asphyxiation (without his helmet). Mar-Vell then truly lost consciousness when the Super-Skrull used the Psycho-Probe on him but secretly revived while his enemy was reviewing his memories of the past few days. Mar-Vell managed to break free of his bonds and temporarily immobilize the Super-Skrull but realized that he was still too weak to face an enemy who possessed the powers of the entire Fantastic Four so his only hope was to flee, but only after recovering and donning his helmet so that he could breathe more easily. Pursued by the Super-Skrull, Mar-Vell flew upwards towards space until his foe, unaware that he was heading towards the orbiting but hidden Kree starship Helion, broke off his pursuit, believing that Mar-Vell was dooming himself by flying into the void of space. However, Mar-Vell was able to barely reach the Kree starship where he obtained information he needed to defeat the Super-Skrull, then returned to the base to battle the Skrull, defeated him with his own super-hypnosis power, retrieve his cylinder, deactivated it just in time, and commanded the Super-Skrull to flee in his spacecraft.

(Captain Marvel I#7 - BTS) - After seemingly proving his loyalty to the Kree Empire by releasing the deadly Z-3 Virus in an Earth community where it killed the entire population (who were secretly robot mannequins made to look entirely human), Mar-Vell returned to the Kree starship to replenish his breathing potion.


(Captain Marvel I#10 - BTS) - After defeating Cyberex, the killer robot that the real Dr. Lawson had created, Mar-Vell had to return to the Kree starship to replace his damaged battle suit with a new uniform and renew his "Kree air supply."


(Silver Surfer III#5) - Sent by the Supreme Intelligence to confirm its deduction that the Skrulls had lost their shape-changing powers, the Kree starship carrying Captain Tar-Rell of the Primary Espionage Unit arrived at the Skrull planet Tarakar. The commander ordered Tar-Rell to get into his battle suit and to prepare for landing, stating that Medic Eine would administer the breathing potion to him. Puzzled, Medic Eine asked, "Only to Captain Tar-Rell, sir? What about the rest of the landing party?" Tar-Rell told her that there would be no landing party because it would take but one Kree to spy upon the accursed Skrulls, and confirm the Supremor's deduction that they had lost their power. Soon afterwards, the starship, cloaked in its Aura of Negativism, descended until it was close enough to the planet's surface for Tar-Rell to leap from it and use his suit's air-jet belt to land safely. Once on the surface, Tar-Rell used the contents of his carry-all cylinder to disguise himself as a Skrull. Unfortunately for him, his mission soon ended badly.

Comments: Created by Stan Lee, Gene Colan and Frank Giacoia.

   The breathing potion that Medic Una prepared for Captain Mar-Vell was in the form of a liquid that gave off visible vapors even as he drank it. However, when Medic Eine was ordered to administer the breathing potion to Captain Tar-Rell, she appeared to be holding a large hypodermic needle in her hand, suggesting that that breathing potion was one that had to be injected. However, since that story never confirmed that what she was shown holding was the breathing potion, it could have been something else and the breathing potion that she administered off-panel could still have been in a drinkable form.
    Potion comes from Latin "potio," meaning drink; potio is also the basis of the word "potable," meaning drinkable. So, it would imply that the Kree breathing potion was a drink. However, not everyone may know that, and Steve Englehart and/or Marshal Rogers may have had the potion drawn as an injectable product. If it was injectable, then solution or formula would have been better terms.

   The idea that Captain Mar-Vell (and, by extension, all Kree) would be unable to breathe in Earth's atmosphere without using the breathing potion was originated by his creator, Stan Lee, who apparently believed that every superhero needed to have some sort of notable weakness. The fact that Thor would change into his human form of Don Blake if his hammer Mjolnir was not touching him for 60 consecutive seconds is another example. However, Mar-Vell's weakness seems to have been more unworkable and thus was later almost always ignored, even in situations when it should have been relevant (like when "Lawson" had to travel with General Bridges and Carol Danvers on a plane from the Cape to New York City in Captain Marvel I#4). However, no official or in-universe explanation for why this weakness was no longer applicable has ever been provided.

To Breathe or Not to Breathe
   The History section above lists the only five stories set in the "mainstream" Marvel Universe in which the Kree breathing potion appears and/or Mar-Vell's inability/difficulty in breathing Earth's air is shown, plus the two stories in which the breathing potion was mentioned but not depicted. That's a total of seven stories in the fifty-five years since the Kree race first appeared in Fantastic Four I#65.

   However, there are two other stories in which the Kree inability to breathe Earth's air is relevant but they are set in alternate timelines. The first was the third story in What If? I#17 (October, 1979) in which the question "What If Captain Marvel Was A Villain?" was answered. In this timeline, known as Reality-79102, Colonel Yon-Rogg was relieved of command by Ronan for his disgraceful actions and, blaming Mar-Vell, he stole a shuttlecraft, traveled to Earth and managed to defeat Mar-Vell. However, as he stood over his hated enemy and prepared to use his own Uni-Beam to destroy him, Yon-Rogg suddenly couldn't breathe and collapsed. Watching this, Mar-Vell thought, "He must have left the ship without taking breathing serum with him -- and without a helmet, he has no way of breathing in this atmosphere!" As a result, this alternate Yon-Rogg became the first (and only) Kree who has ever been shown dying by breathing Earth's air.

   The second story was published in Marvel Fanfare#51 (June, 1990) but was a "displaced" comic that had been intended to be the first issue of a 12-issue Silver Surfer maxi-series that was abandoned when Marvel decided to give the Silver Surfer an ongoing series instead. In this story, written by Steve Englehart, a Kree starship tries to kill the Silver Surfer and most of its crew dies as a result but two survive and make their way to Earth. While searching for them, the Surfer thinks to himself, "Earth's atmosphere is poisonous to the Kree -- thus they must use special apparatus to breath -- and the excess of nitrogen it leaves will alert me, once I come close enough to sense it!" The two Kree are later seen to be using breathing helmets, but they ultimately die by other causes. This is the only comic in which Earth's air is described as being "poisonous to the Kree."

   Mar-Vell's inability to breathe in Earth's atmosphere is a plot point mentioned in four of his first five stories and then, as pointed out by an article at that can be found here, was essentially forgotten. That article suggests that the ability to breathe on Earth that he later exhibited was one of the powers that he received from "Zo" in Captain Marvel I#11 and, for all I know, maybe it was. But what about all the other Kree who have visited and/or lived on Earth without the slightest indication that they needed help?

   Although Mar-Vell's inability to breathe Earth's air may have been forgotten a little over a year after his first appearance, the fact that it was a weakness of the Kree race was not. The entry on the Kree that appeared in The Official Handbook of the Marvel Universe I#6 (June, 1983) stated, "Outwardly humanoid to a large degree, Kree bodies are adapted to environmental conditions on Hala that are un-Earth-like: notably, higher gravity and a higher nitrogen content in the atmosphere. Although the Kree cannot breathe Earth's atmosphere without special apparatus, their denser bodies afford them about twice the average human being's strength and endurance." As far as I know, this information has been repeated in every version of the Official Handbook that has been published since then and it thus remains canon. The question is, should it be?

   Since Mar-Vell last needed "Kree air" in 1969, a number of Kree have appeared in stories in which they visited Earth. Although most of them were warriors (like Ronan) who wore uniforms with helmets that could have provided life-support, there were also some individuals who spent time on Earth without wearing helmets, including Falzon, Shatterstar (Arides), Doctor Mac-Ronn, Doctor Tara, and Doctor Minerva (Minn-Erva). Also, in the 1975 story that revealed how a Kree colony was founded on Earth millennia ago, the first two Kree settlers, Son-Dar and Teress, were also depicted without helmets and their descendants, the Priests of Pama who raised Mantis, were never shown having to wear helmets.

   So, how can this apparent discrepancy in the ability of Kree to breathe normally in Earth's atmosphere be explained? It seems to me that there are three possible solutions. The first possibility is that Kree bodies are normally adapted to a higher nitrogen content but that Kree doctors have developed a treatment that can permanently alter Kree physiology so that they can function normally in atmospheres with a lower nitrogen content than Hala. Since this would basically be an improvement on the breathing potion, it seems quite plausible, but it does seem a bit oddly convenient that it was developed (or became available) only after Mar-Vell's mission on Earth.

   The second possible explanation is that, although Kree bodies are adapted to a higher nitrogen content, they possess the natural ability to become acclimatized to atmospheres with somewhat lower nitrogen contents. However, the process may take some time, just as it can take months or even years for humans to acclimatize to life in high altitude environments that have lower oxygen levels. If this were true, then the breathing potion would actually be an artificial way to instantly acclimatize Kree to such environments, with the drawback being that the artificial nature of the acclimatization meant that it would only be temporary. Kree who had already naturally acclimatized to such atmospheres would perhaps retain that acclimatizion for some time, perhaps even permanently, and this would enable them to travel to and function on planets like Earth without needing either the breathing potion or special apparatus.

   Although probably not intended as such by writer Roy Thomas, two of the issues that he wrote do contain what could be interpreted as subtle evidence that Mar-Vell was slowly becoming acclimatized to Earth's atmosphere. Consider the following: At the end of Marvel Super-Heroes II#12, after the breathing potion's hour of effectiveness had run out, Mar-Vell states that he "can't breathe" and has to put on his helmet. However, early in Captain Marvel I#2, after taking off his helmet, he states that he "can hardly breathe." And then in Captain Marvel I#3, although he worries about dying by asphyxiation once his "life-giving helmet" has been removed, he recovers it and dons it so that he "can breathe more easily." Should this be taken as evidence that he was finding Earth's air slightly less unbreathable than he had when he first arrived? Or am I reading too much into the words that Roy Thomas chose for him?

   The third possibility is that the inability to breathe normally in some un-Hala-like atmospheres may be an artificial weakness, one that is secretly induced in some Kree agents by their superiors in order to create a life-threatening dependency on the breathing potion that forces them to remain "loyal" in order to survive. If this were true, then the "breathing potion" itself would actually be an addictive drug and the apparent inability to breathe a given atmosphere would be a withdrawal symptom that had been designed to be triggered by the passage of a set period of time. Exposure to a Hala-like atmosphere or consumption of another dose of the potion would be enough to instantly cancel those withdrawal symptoms and seemingly restore the affected Kree's ability to breathe normally. The addictive effect of the potion could be permanent (unless counteracted by a drug that somehow completely neutralized the user's dependence) or the potion could have been designed to neutralize itself if the infected/addicted Kree stayed within a Hala-like environment for a prolonged time.

   I prefer the acclimatization theory (because there seems to be the tiniest bit of in-story evidence supporting it) but the secret way to compel loyalty theory seems very Kree-like. I guess we'll just have to wait and see what explanation becomes canon. Of course, since over fifty years have passed without anybody at Marvel addressing this situation, who knows how long that could take?

   One final thought. The first Captain Marvel story introduced the idea that "the pull of gravity is far stronger in the Kree Galaxy than it is on Earth" and that Official Handbook entry established that Hala's atmosphere had a higher nitrogen content than Earth's atmosphere. However, when humans (and other beings) from Earth have visited Hala, they have NEVER demonstrated any negative effects from being in an un-Earth-like environment. None of them have ever even mentioned feeling heavier on Hala than they did on Earth and none of them have had any trouble breathing on Hala, even when exerting themselves by running and/or fighting. The fact that nobody has ever bothered to quantify exactly how different Hala's gravity and atmosphere are from those of Earth probably just makes it easier for writers to ignore the fact that they ARE supposed to be different, and that apparent similarity makes the idea that Kree could having trouble breathing Earth's air seem unlikely and contrived. Which, of course, it was.

Profile by Donald Campbell.

The Kree breathing potion has no known connections to

images: (without ads)
Marvel Super-Heroes II#12, page 3, panel 4 (Mar-Vell drinking the breathing potion)
      page 3, panel 2 (Medic Una pouring the breathing potion)
Captain Marvel I#2, page 6, panel 3 (Mar-Vell can hardly breathe)
      page 6, panel 5 (breathing potion in its pure form)
Silver Surfer III#5, page 10, panel 1 (Medic Eine holding a hypodermic needle)

Marvel Super-Heroes II#12 (December, 1967) - Stan (The Man) Lee (writer/editor), Gene (The Dean) Colan (artist), Frank Giacoia (embellisher)
Marvel Super-Heroes II#13 (March, 1968) - Roy (The Boy) Thomas (writer), Gene (The Dean) Colan (artist), Paul Reinman (embellisher), Stan (The Man) Lee (editor)
Captain Marvel I#2 (June, 1968) - Roy Thomas (writer), Gene Colan (artist), Vince Colletta (inker), Stan Lee (editor)
Silver Surfer III#5 (November, 1987) – Steve Englehart (story), Marshal Rogers (pencils/colors), Josef Rubinstein (inks), Michael Higgins (editor)

Mentioned only in:
Captain Marvel I#7 (November, 1968) - "Super Nova" Arnold Drake (writer), "4th Dimensional" Don Heck (penciler), "Solar Swinger" John Tartaglione (inker), "Speed O'Light" Stan Lee (editor)
Captain Marvel I#10 (February, 1969) - Arnold Drake (writer), Don Heck (penciler), Vinnie Colletta (inker), Stan Lee (editor)

First Posted: 07/24/2022
Last updated: 07/24/2022

Any Additions/Corrections? please let me know.

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