Gallifreyan physiology Gallifreyan s were outwardly indistinguishable from human s . Although they looked identical to humans and many humanoid s , they had a variety of biological differences that set them apart . They also possess multi - dimensional aspects . Taxonomy . Gallifreyans were classified by human s as " Dominus temporis " . ( PROSE : " The Last Dodo " ) External appearance . Externally , Gallifreyans were usually identical to humans , though they tended to have a mostly European / Caucasian appearance . Hair and eye colour were of any colour found among humans . ( PROSE : " The Last Dodo " ) Teeth were indistinguishable from human teeth . ( TV : " The Gunfighters " , " Utopia " ) However , while Romana I was regenerating into Romana II , she took on various appearances varying in height and build , and even one with blue skin . ( TV : " Destiny of the Daleks " ) The Ninth Doctor referred to the regeneration process as " dodgy " , and indicated that it was possible to regenerate without a head . ( TV : " The Parting of the Ways " ) One visible difference between humans and Time Lords was the eye . ( TV : " Doctor Who " ) While the human eye was just a dish of light - sensitive cells , leaving the brain to do all of the processing , the Time Lord retina was capable of thinking on its own . As a result , on Gallifrey , the retina replaced fingers as the main method of communicating with machines . ( PROSE : " Seeing I " ) The Eighth Doctor ' s eyes could change colour between green , blue , ( PROSE : " Vampire Science " ) and grey . ( PROSE : " Mad Dogs and Englishmen " ) The Master ' s eyes could change colour from dark brown , flecked with gold , to midnight blue , to a deep purple . ( PROSE : " Doctor Who and the Dæmons " ) Allisheer St Marx , the half - human daughter of Handramit , had mirror - flecked eyes ; ( PROSE : " Of the City of the Saved . . . " ) Antigone ' s dark eyes were flecked with the tell - tale purple of the Homeworld high - caste . ( PROSE : " Weapons Grade Snake Oil " ) But Time Lords ' physical forms are only fragments of much vaster multi - dimensional ones existing in a realm invisible to humans , this aspect is able to create coincidences around a Time Lord ( PROSE : " Christmas on a Rational Planet " , " Sky Pirates ! " , " Deceit " , " The Taking of Planet 5 " ) Resilience . Gallifreyans were , on the whole , extremely tough and resilient . An average Gallifreyan was superior to a human at their peak . ( PROSE : " Doctor Who and the Terror of the Autons " ) Gallifreyans could survive some falls which would shatter the bones of humans . The Tenth Doctor survived a fall from a low flying spaceship through a glass skylight and was able to stand and move afterwards . ( TV : " The End of Time " ) However , the fall from a radio telescope dish was enough to cause the Fourth Doctor to regenerate . ( TV : " Logopolis " ) Gallifreyans could survive extreme cold , ( TV : " The Tomb of the Cybermen " , " The Seeds of Doom " , " The Ribos Operation " , " 42 " , " The Infinite Quest " , " Planet of the Ood " ) due to having a " souped - up metabolism " ( COMIC : " The Betrothal of Sontar " ) ; they could even withstand exposure to a vacuum for a few minutes with the only consequence being blind ness rather than death ( TV : " Oxygen " ) . They could also survive extreme heat . ( TV : " The End of the World " ) They could even survive the subzero temperatures and extremely low pressure of vacuum for around six minutes , ( TV : " Four to Doomsday , The Doctor , the Widow and the Wardrobe " ) and survive electric shocks that would be fatal to humans . ( TV : " Genesis of the Daleks " , " Terror of the Zygons " , " World War Three " , " Evolution of the Daleks " , " The Vampires of Venice " , " The Pandorica Opens " , " The Zygon Inversion ; " AUDIO : " Spare Parts " ) Röntgen radiation affected Gallifreyans so minimally that Gallifreyan children were routinely given radioactive toys in the nursery . They could , at will , absorb very high doses of Röntgen radiation , transform it into a form harmless to humans , and expel it from their bodies . ( TV : " Smith and Jones " ) Radiation of other kinds could be fatal , but even then a Gallifreyan could handle much higher doses than a normal human could , and could hold out much longer than even most terrestrial life - forms ( TV : " Planet of the Spiders " , " The End of Time " ) , although a unique form of radiation around the Lakertyan System was only fatal to Time Lords while being harmless to humans ( AUDIO : " The Brink of Death " ) . Gallifreyans needed less sleep than humans , and could make do with as little as an hour . ( TV : " The Talons of Weng - Chiang " , " Mummy on the Orient Express " , HOMEVID : " Night and the Doctor " , PROSE : " The Highlanders " ) A Gallifreyan who was severely injured without actually needing to regenerate to heal the damage would generally slip into a healing coma , and devote all his or her energy to healing the injury . While in the coma , they would appear to be dead . ( TV : " Inferno " , " Planet of the Daleks " , PROSE : " EarthWorld " , " Vanishing Point " ) Time Lords also seem to have an increased resilience to higher frequencies of sound . ( TV : " The Christmas Invasion " , " Partners in Crime " ) Gallifreyans could be disabled by a blow to the left shoulder , which possessed a vulnerable nerve cluster . ( PROSE : " Set Piece " ) Gallifreyans also appeared capable of resisting attempts to disintegrate their bodies , as Sycorax whip s ( TV : " The Christmas Invasion " ) and electric bolts from Zygon s ( TV : " The Zygon Inversion " ) , both of which were shown capable of disintegrating other organisms , did not affect them . Based on the similarities between Mal ' akh regenerative ability and that of Gallifreyans and Time Lord s , Richard Francis Burton hypothesized that early Gallifreyans deliberately infected themselves with the Yssgaroth taint to give themselves a biological advantage . ( PROSE : " The Book of the War " ) Lifespan . Even without regeneration , Gallifreyans had considerable lifespans . Within one regeneration , Gallifreyans could live for hundreds of years , yet look much younger than a human of equivalent age . When artificially aged 500 years , the Fourth Doctor looked like an elderly human . ( TV : " The Leisure Hive " ) During his eighth incarnation , the Doctor spent over a century trapped on Earth ( PROSE : " The Ancestor Cell " to " Escape Velocity " ) and never seemed to physically age during that time , he then spent approximately 600 years in the planet Orbis ( AUDIO : " Orbis " ) . Physical stress could cause Gallifreyians to age . The Second Doctor ' s hair turned from black to grey after the stress of his confrontation with the Player s as they attempted to alter the outcome of the Napoleonic Wars ( PROSE : " World Game " ) . The War Doctor , appearing as a young man at the beginning of his life , ( TV : " The Night of the Doctor " ) . looked considerably older at the end of his life ( TV : " The Day of the Doctor " ) after fighting in the Time War , an event that lineally lasted 400 years , but was more like an eternity . ( PROSE : " Engines of War " ) The Ninth Doctor was once sent back in the past , and waited 28 years before seeing Rose again , and looked just the same as the day they were separated . ( AUDIO : " The Other Side " ) When the Tenth Doctor was artificially aged 100 years by the Master ' s laser screwdriver , he took on the appearance of a very old man . Ageing him a further 900 years turned the Doctor into a small , grey - skinned figure . ( TV : " The Sound of Drums " / " Last of the Time Lords " ) The Eleventh Doctor looked essentially the same for two centuries , ( TV : " The Impossible Astronaut " ) though at least three more centuries caused him to age somewhat and six more centuries ( PROSE : ) of further time caused him to age into a very old man , near death from old age . ( TV : " The Time of the Doctor " ) However , Gallifreyan children grew at about the same rate as humans of the same age . ( TV : " The Sound of Drums " ) After this point , ageing would slow , with the Gallifreyan looking like a teenager for decades . ( PROSE : " Legacy of the Daleks " ) The Tenth Doctor referred to himself at ninety years old as being " just a kid " . ( TV : " The Stolen Earth " ) The Second Doctor once stated that , barring accidents , his people could " live forever " . ( TV : " The War Games " ) The Doctor once said that he considered himself at approaching 750 to be middle - aged . ( TV : " Pyramids of Mars " ) One Time Lord , Quences , was killed when he was over 7 , 000 years old . ( PROSE : " Lungbarrow " ) Professor Chronotis suffered from senility when over 12 , 000 years old ( PROSE : " Shada " ) , and the Eleventh Doctor showed some signs of the same on the brink of his thirteenth and supposedly final death at " over 2000 " years old . ( TV : " The Time of the Doctor " , " Deep Breath " ) Senses . Gallifreyans had all the senses possessed by humans , and to generally superior degrees . Gallifreyans also had extraordinary reflexes and precision timing , literally superhuman . ( PROSE : " Doctor Who and the Terror of the Autons " , TV : " The End of the World " , " The Doctor ' s Daughter " ) The Third Doctor stated that their reflexes were ten times a human ' s . ( TV : " The Time Monster " ) To protect himself and Malady Chang from rifle fire shot at them by Jonah Cosgrove , the Eighth Doctor demonstrated his reflexes by using a pistol to shoot the incoming bullets harmlessly out of the air . ( PROSE : " Trading Futures " ) In the space of four nanoseconds , an incarnation of the Doctor moved fast enough to dodge shots fired at him by fifty invisible and indestructible android assassins , whilst devising a plan to use the energy from their attacks to charge a vortex manipulator and escape . ( TV : " The Witch ' s ' Familiar " ) Missy later utilised this tactic to escape from the cyber - converted Brigadier ( TV : " Death in Heaven " ) and several Dalek s ( TV : " The Witch ' s ' Familiar " ) , all whilst giving the impression that she was killed in the blasts . Gallifreyans showed great hand - eye coordination and dexterity with a wide variety of tool and weapons . ( TV : " The Android Invasion " , " The Pirate Planet " ) Gallifreyans ( in " younger " bodies ) were , consequently , very physically able and highly athletic . The Third Doctor was a master of Venusian aikido , ( TV : " Inferno " , " The Mind of Evil " , " Colony in Space " , " The Mutants " , " The Green Death " ) et al . ) the Fifth Doctor was a skilled cricketer , ( TV : " Black Orchid " ; AUDIO : " Autumn " ; PROSE : " Goth Opera " ) and the Eleventh Doctor discovered a natural talent for football . ( TV : " The Lodger " ) Gallifreyan eye s were better at seeing in general , as well as in the dark , as they could gather and enhance available light . ( PROSE : " Lucifer Rising " ) They could notice incredible amount of detail from distances of at least one hundred yards away , ( TV : " The Eleventh Hour " ) as well as people that were well beyond the human line of sight . ( TV : " The Hungry Earth " ) Gallifreyans had incredibly precise control of their eyes . ( PROSE : " Seeing I " ) The Tenth Doctor perceived sounds from the TARDIS , while located several sections away , aboard the airship " Valiant " . ( TV : " The Sound of Drums " ) Gallifreyans were capable of identification by taste . This included blood , ( TV : " The Christmas Invasion " , PROSE : " Bad Therapy " ) wood type , ( TV : " Tooth and Claw " ) , gunpowder ( TV : The Visitation ) , plastic composition , ( TV : " The Idiot ' s Lantern " ) age of an object , ( TV : " The Eleventh Hour " ) origin of an object ( TV : " Day of the Moon " ) or the atmospheric composition . ( TV : " The Time of Angels " , " Dinosaurs on a Spaceship " ) The Gallifreyan sense of smell was equal to their sense of taste . ( PROSE : " Wishing Well " ) They could do a chemical analysis of the air using their sense of smell . ( PROSE : " Doctor Who and the Carnival of Monsters " ) On some occasions Time Lords were also able to judge what time period and location they were in by the smell of the air . ( TV : " The Unicorn and the Wasp " , " The Time of Angels " ) The Second Doctor knew the Master had tricked Jamie when he smelt the Master ' s handkerchief . ( PROSE : " The Nameless City " ) Gallifreyans were better at coping with sudden changes in position than humans and were harder to disorient . ( AUDIO : " The Forever Trap " ) As well as the senses shared with humans , Gallifreyans had further senses , with at least a sixth sense , ( PROSE : " Wishing Well " ) although the Doctor tended to keep his sensory input limited to the human norm to make things more interesting and allow himself to be surprised . ( PROSE : " Eye of Heaven " ) Gallifreyans had time - and spatial - related senses and physical attributes ; they were able to resist fields of slow time , ( TV : " The Time Monster " , " Invasion of the Dinosaurs " ) notice distortions and jumps in time , ( TV : " Invasion of the Dinosaurs " , " City of Death " , " The Lodger " ) retain perception of local time flow , including a secondary " backwards " consciousness during jumps back in time that could overwrite the one prescribed by forward time , ( COMIC : " Space in Dimension Relative and Time " ) directly perceive the interstellar motions of cosmological bodies or their inhabitants ( TV : " Rose " ) — including sensing the " shape " of the world to the extent that they were aware when trapped in pocket dimensions such as Lychburg ( PROSE : " Heart of TARDIS " ) — and perceive all possible timelines . ( TV : " The Parting of the Ways " , " The Fires of Pompeii " ) Gallifreyans could sense the presence of others of their own species , with the sense being specific enough to allow identification of one another just by sight , regardless of potential recent regeneration . ( TV : " The Sound of Drums " ) Due to their time sensitive nature , Gallifreyans could retain memories of negated ( TV : " Journey to the Centre of the TARDIS " ) or alternative ( TV : " The Name of the Doctor " , " The Time of the Doctor " ) timelines . Internal anatomy . Body temperature . According to Tom Cardwell ' s bioscan , the Eighth Doctor had a body temperature of fifteen degrees Celsius . ( AUDIO : " Blood of the Daleks " ) While recovering from a serious injury , it could drop spontaneously to below - freezing temperatures . ( TV : " Planet of the Daleks " ) The Eighth Doctor and Miranda Dawkins could both demonstrate this lower body temperature on a cold night , their breath not visible while other humans ' was . ( PROSE : " Father Time " ) The brain . The Time Lord brain was much larger and more complex than the human brain . The size differences effectively ruled out brain transplant s from a Gallifreyan to a human . ( TV : " The Brain of Morbius " ) They had either one brainstem , ( TV : " The Magician ' s Apprentice " ) or three . ( TV : " Extremis " ) Time Lords had a form of eidetic short - term memory , able to recall every insignificant detail of even the most moments in time . ( TV : " The Eleventh Hour " ) The Timewyrm noticed that on a quantum level , the Seventh Doctor ' s brain could receive information from possible futures , possibly without even realising it consciously . ( PROSE : " " ) Time Lords could also separate the hemispheres of their brain , allowing them to multitask easily . ( PROSE : " Island of Death " ) Records on some planets indicated isolated cerebral hemispheres as a characteristic of Time Lords . ( COMIC : " Doctormania " ) Time Lords had an additional brain lobe dedicated to mechanical and other bodily functions , freeing the other lobes for intellectual endeavours . ( AUDIO : " Spare Parts " ) The autonomic functions could be artificially supplanted with a special device , allowing the Gallifreyan to think with their autonomic brain . ( PROSE : " Shada " ) Time Lords displayed the ability of touch - enabled mental manipulation ; this manifested itself in a number of different ways , including hypnosis , ( TV : " Terror of the Autons " , " The Ribos Operation " , " Fear Her " ) mind - reading , ( TV : " The Girl in the Fireplace " ) thought sharing , ( TV : " The End of Time " ) the ability to relieve dementia , ( TV : " The Shakespeare Code " ) putting others to sleep , ( TV : " Listen " ) mentally influencing the dreams of others ( TV : " The Eleventh Hour " ) and memory erasure . ( TV : " Journey ' s End " ) They could also transfer knowledge quickly to another person by headbutting them . ( TV : " The Lodger " ) Time Lords were telepathically linked to one another and could join the entire Time Lord intelligence as one . ( TV : " The Invisible Enemy " ) They could hold telepathic conversations over distances , but this was more difficult . ( TV : " The Sensorites " , " The Three Doctors " , " The Pirate Planet " ) They could converse with each over the astral plane , although this ability required intense concentration , and an interruption might have fatal consequences for the Time Lord . ( TV : " The Two Doctors " ) Their telepathy extended to less intelligent animals . ( TV : " The Lodger " ) Perhaps because of this , they had an innate ability to understand any language . ( PROSE : " Warring States " ) In ancient times , Gallifreyans who were capable of blocking out the telepathic thoughts of other Gallifreyans were called Individuals . They usually had red - gold hair and often went on to become Young Heroes . ( PROSE : " " ) They were highly resistant against , if not immune to , other forms of mind control . ( TV : " The War Machines " , " The Green Death " ) However , they were vulnerable to more powerful forms of mind control , such as the Morpho , ( TV : " The Velvet Web " ) the Great Vampire s ( TV : " State of Decay " ) or Sutekh ( TV : " Pyramids of Mars " ) employed . Time Lords had an instinctive gut revulsion towards fixed points in time . An example of this was Jack Harkness , who was granted immortality by Rose Tyler . ( TV : " Utopia " ) Skeletal structure . Gallifreyan skeletal structure was reported to have been identical to human skeletal structure , with one exception . In some accounts , the Gallifreyan rib cage had " extra ribs " ( AUDIO : " Black and White " ) or more specifically 26 rib s , two more than humans . ( PROSE : " Blood Heat " ) Other sources suggested that they had 24 ribs . ( TV : " Spearhead from Space " ) Circulatory system . Gallifreyan blood was different from human blood , darker and with a slight orange tinge to it . ( TV : " The Two Doctors " , PROSE : " The Left - Handed Hummingbird " ) The differences were readily apparent under a microscope . ( TV : " Spearhead from Space " , " The Invisible Enemy " , " Doctor Who " ) It was highly adaptive , with regenerative properties . ( PROSE : " The Art of Destruction " ) Gallifreyan blood had temporal platelet s , allowing for a more " ad - hoc " recovery from injury not serious enough to require regeneration . ( AUDIO : " The Bride of Peladon " ) It didn ' t have the same A and B types as human blood ( i . e . , the A and B antigens were not present ) , but different blood types still existed with Romana II noting that her blood was not compatible with the Fourth Doctor when he was badly injured by vampire s , requiring him to receive a transfusion from his future self . ( PROSE " The Eight Doctors " ) The extra - cellular matrix was incompatible with Earth - based life and the structure of haemoglobin was different . ( PROSE : " The Art of Destruction " , TV : " The Invisible Enemy " , PROSE : " Placebo Effect " ) The Tenth Doctor explained to Christina that fried bread would clog arteries , but he had " tiny things " inside his blood that " sluice [ d ] it out again . " ( PROSE : " Keeping up with the Joneses " ) Binary vascular system . Gallifreyans naturally born before the time of Rassilon and Pythia had two heart s . ( PROSE : " " , " Lungbarrow " ) Accounts differed as to the vascular systems of Gallifreyans in their first incarnation . Some accounts indicate that Gallifreyans normally had two hearts even in their first body . ( AUDIO : " Frostfire " , TV : " The Doctor ' s Daughter " ) Other accounts indicated that Gallifreyans Loom ed after the Pythia ' s curse of sterility originally emerged with a single heart and gained their second only after their first regeneration , ( PROSE : " The Man in the Velvet Mask " ) while those of Newblood houses sprang from the Looms with two hearts from the outset . ( PROSE : " Christmas on a Rational Planet " ) A Gallifreyan could survive with only one heart , should the other be punctured , destroyed or otherwise stopped , though he or she would be weakened greatly . ( PROSE : " Managra " , " The Adventuress of Henrietta Street " , TV : " The Shakespeare Code " , " The Power of Three " ) The Eleventh Doctor claimed that he wouldn ' t survive much longer after one of his hearts was stopped by a Shakri cube . ( TV : " The Power of Three " ) A Gallifreyan in total cardiac arrest would need CPR on " both " hearts . ( TV : " Smith and Jones " ) Regeneration would become impossible if both hearts were burnt out simultaneously . ( TV : " Forest of the Dead " ) Gallifreyans could , with training , gain conscious control over their hearts , enabling them to stop their hearts and feign death , ( TV : " Destiny of the Daleks " ) and could slow them down significantly . ( TV : " Terror of the Zygons " , PROSE : " Wishing Well " ) A dual cardiovascular system being more efficient , Gallifreyans in a healing coma could have a resting pulse rate of as few as ten beats per minute . ( TV : " Spearhead from Space " ) The two heartbeats could be mistaken by human cardiologists such as Dr Grace Holloway as " fibrillating badly " . ( TV : " Doctor Who " ) Two pulses could be detected in the wrist . ( TV : " The Five Doctors " , " Time and the Rani " , AUDIO : " Primeval " ) By controlling its heartbeats , a Time Lordcould reproduce Gallifreayan morse code ( WC : " Shada " ) Cybermen from Pete ' s World could detect the presence of a Gallifreyan binary vascular system , and stated that it was an unknown upgrade that would require further analysis . ( TV : " The Age of Steel " ) Respiratory system . In order to use their two hearts , Gallifreyans had an advanced respiratory system . Instead of large lung s , they had a series of pulmonary tube s parallel to the lymphatic system . This made them positively buoyant , allowing them to swim with ease . ( PROSE : " Island of Death " ) They could survive longer without much oxygen , past the point where a human would be unconscious ; ( TV : " The Ark in Space " , " The Two Doctors " , " Smith and Jones " , " Mummy on the Orient Express " , PROSE : " Legacy " ) the Fifth Doctor explicitly claimed to be able to store oxygen for several minutes . ( TV : " The Caves of Androzani " ) Despite this , Gallifreyans ( especially frailer individuals ) could be affected by altitude sickness . ( PROSE : " Marco Polo " ) Like most aspects of Gallifreyan physiology , the respiratory system was largely under conscious control . Gallifreyans could , at will , enter a trance state which reduced the need for oxygen . ( TV : " Terror of the Zygons " , " Four to Doomsday " ) Gallifreyans also had a respiratory bypass system , which allowed them to survive strangulation , ( TV : " Pyramids of Mars " , PROSE : " Human Nature " ) avoid breathing poison gas , ( TV : " The Two Doctors " ) and stave off drowning . ( PROSE : " Killing Ground " ) Gallifreyans were immune to the effect of helium gas , which could make human voices sound high - pitched and squeaky . ( TV : " The Robots of Death " ) Other organs . The skin of a Gallifreyan had more subdural and subcutaneous layers than a human , adding considerably to its durability and damage resistance . Gallifreyan skin tended to reject foreign objects such as subcutaneous implants or tags relatively quickly . ( PROSE : " Burning Heart " ) Implants that went below the subcutaneous layers , such as those that bonded with cartilage , would be retained . ( TV : " Day of the Moon " ) Gallifreyan physiology was described by a human medic as having " four of everything he should have and two of everything else . " ( PROSE : " Burning Heart " ) The Gallifreyans had two liver s . ( PROSE : " Halflife " , AUDIO : " Black and White " ) They also had several organs which had no analogue in humans . ( PROSE : " Placebo Effect " ) Due to internal incompatibilities , Gallifreyans were not suitable for certain forms of Cyber - conversion . ( TV : " Closing Time " ) Gallifreyans also had DNA in a triple - helix formation . ( PROSE : " The Crystal Bucephalus " , COMIC : " Doctormania " , TV : A Good Man Goes to War ) Biochemistry . On the whole , Gallifreyan biochemistry seemed quite similar to human biochemistry : they could eat anything humans could and could breathe on Earth . ( PROSE : " The Left - Handed Hummingbird " ) Gallifreyan biochemistry , like many other aspects of Gallifreyan physiology , was subject to the conscious control of the individual . For example , a Gallifreyan was able to counteract the negative properties of psilocybin by modifying the chemicals into something harmless , though the techniques were not foolproof and drug overdose s were still possible . ( PROSE : " The Left - Handed Hummingbird " ) Similarly , though Gallifreyans were susceptible to the intoxicating effects of alcohol , they could easily shrug off the effects when they needed to . ( PROSE : " The Quantum Archangel " ) As with humans , however , excessive consumption could produce a hangover . ( AUDIO : " Slipback " ) Ginger beer would reduce their ability to tolerate alcohol ( AUDIO : " The Kingmaker " ) , although the Sixth Doctor later reflected that his immediate predecessor wasn ' t a strong drinker while his fourth self , like his current incarnation , enjoyed the chance to get drunk ( PROSE : " The Quantum Archangel " ) . Some human medicines seemed to work on Gallifreyans as well as humans . Anaesthetic gasses of the type commonly administered before surgery , however , did " not " work well on Gallifreyans ; a much greater quantity of anaesthetic could be administered , and even then it might not work completely . Anaesthetic could , however , almost destroy the process of regeneration ( TV : " Doctor Who " ) , although there is no clear evidence that the drug alone would cause the Time Lord to regenerate as the Doctor died during a botched attempt to operate on him in the belief that he was experiencing heart trouble . Other sleep - inducing drugs might work on a Gallifreyan , but would take roughly twice as long as with humans , even if the Time Lord in question took double the dosage that the humans had . ( TV : " The Androids of Tara " ) Aspirin was toxic to Gallifreyans ; a single dose could kill one . ( TV : " The Mind of Evil " , PROSE : " The Left - Handed Hummingbird " ) It was said to either fatally stop platelet aggregation , ( AUDIO : " The Condemned " ) cause massive allergic , pulmonary and cerebral embolism , ( PROSE : " Burning Heart " ) or interfere with the hormone receptor intermediaries . ( PROSE : " The Taking of Planet 5 " ) Death could be prevented by entering a deep coma which was outwardly mistakable for death , ( PROSE : " Burning Heart " ) or by ingesting chocolate . ( AUDIO : " The Condemned " ) Gallifreyans were as susceptible as humans to the devastating effect of spectrox poisoning ; spectrox toxaemia proceeded at roughly the same rate in both species , though a Gallifreyan , being tougher , would not succumb as quickly . ( TV : " The Caves of Androzani " ) They " could " counteract cyanide poisoning , given a number of ingredients including ginger beer , something salt y ( but not salt ) , protein and a physical or mental shock , but only if done very soon after the cyanide is ingested . ( TV : " The Unicorn and the Wasp " ) Other types of poison could have a very different impact on Time Lords ; the Fifth Doctor was once infected with a poison that would have been fatal to a human within a few minutes , but he merely spent the next few hours in a coma and woke up the next morning asking for breakfast as though nothing had happened ( AUDIO : " The Eye of the Scorpion " ) . Mustard gas would kill a Gallifreyan as much as a human , though Gallifreyans were far more susceptible to aid for mustard gas . ( AUDIO : " The Great War " ) The Eighth Doctor was once able to survive ingesting mustard gas when he was trying to trick the clock - faced people into believing that he had committed suicide in his past , using the gas to account for the amnesia that was actually caused by his future self ' possessing ' his past self ( PROSE : " Anachrophobia " ) . And the sixth Doctor was able to survive a mustard gas trap left by The Rani ( TV : Mark of the Rani ) During a decontamination attempt by Silurian s intended for human s , the Eleventh Doctor claimed that removing human germs would remove half of the things keeping him alive . ( TV : " Cold Blood " ) Time Lords did not need to brush their teeth like humans , because their bodies did not allow for the same type of tooth decay . However , the Tenth Doctor enjoyed brushing his teeth because he liked the feel of the mint y froth on his tongue . ( PROSE : " Keeping up with the Joneses " ) Like humans , Time Lords were capable of having allergic reactions to specific substances . The Fifth Doctor stated that he was allergic to certain gas es in the Praxis series , and that he could eat the celery stalk on his left lapel in order to counteract the reaction . ( TV : " The Caves of Androzani " ) Rosemary could also make the Fifth Doctor sneeze when he tasted it in his drink ( TV : " Castrovalva " ) , and he speculated that he was allergic to something in the air when he sneezed while visiting Suffolk in 1911 ( AUDIO : " Moonflesh " ) .