Simply put, the notion that time travel makes one physically ill. May be merely annoying, or potentially fatal.
Usually, it is stated or implied that this illness is due to repeated jumps through time, and thus has the effect of limiting the characters' ability to take advantage of potentially story-breaking technology.
May cause disorientation that results in someone demanding to know from passersby what year it is.
- Kyon from Haruhi Suzumiya experiences this every time he (consciously) time travels with Asahina, one incident being seen in the first episode of Haruhi 2009, where they go off to help Haruhi write a message to some random aliens, turning out to start off the whole premise of the story. He talks about the world turning around and wanting to puke (in the novels).
- Mizuki's time travel artifact from Kamisama Kiss exerts a physical toll on the person directly proportional to the amount of time they spend in the past. After one trip, Nanami couldn't hardly move for a few days.
- Sailor Moon: When Usagi and the Outer Sailors were standing in a elevator-like time portal in the manga, Usagi suddenly starts banging on the glass and complaining that she was going to puke. She never actually does though. And of course, Haruka has to go and make fun of her.
Haruka: Not even Super Sailor Moon can battle the forces of gravity.
- When the Justice League traveled several thousand years into the past, the human members got sick for a while. Batman was sick the longest because he is the most 'normal'. Green Lantern had some protection but he still got sick. The Flash recovered the fastest because of his super metabolism but he wouldn't recommend recovering that way.
- Star Trek: Early Voyages: In "Now and Then, Part Three", Dr. Gabrielle Carlotti's examination of Mia Colt determines that her temporal integrity is breaking down. Saavik speculates that the timeline is rejecting her as she is alien to it. If she is not returned to her proper time and place, she will die within four days.
- Transformers: More than Meets the Eye: Anode was told that she was suffering from timesickness after being awoken from her sleeper pod. Feeling moody, she instead went off to hang out with her friend Lug. When Lug disappeared on her, Anode went looking for her, only to discover that nobody knew of an Autobot named Lug- she'd been a timesickness-induced hallucination the whole time. The real Lug was dead, but thanks to her spark being preserved, Anode was able to bring her back by implanting it into a protoform.
- In Memento Vivere, a Final Fantasy X fanfiction, Rikkus inexplicable seizures cause the others to assume she has health problems.
- Magicae Est Potestas, a crossover between Artemis Fowl and Undertale, is also an example. Time travel has been shown to cause memory loss, rearrangement of body parts, or physical and mental de-aging in the Artemis Fowl series already, but so does Mental Time Travel - aka the Resets. Going too back far in time after too many Resets is what caused the Genocide runs. Runs, because this has happened twice.
- In What Tomorrow Brings, the time-displaced Animorphs keep throwing up on the first few days. Turns out it was food from the original universe that was still in their systems.
- 12 Monkeys: The process of time travel seems to cause psychological harm. This is explained early, as Cole relays rumors that the other inmates who Got Volunteered for the trip wound up in the psych ward.
- The scientists responsible for the project tell Cole that he possesses a mental resilience that makes him a good candidate for time travel: an ability to remember facts and details. He is not unscathed though, as he can Go Among Mad People and fit in perfectly.
- Dr. Railly's research draws attention to the phenomenon of Doomsayer prophets: strange people spouting half-coherent Cassandra Truth about an incoming plague and the end of the world. It is suggested (but not confirmed) that every such Mad Oracle in history is like Cole: flung into the past, driven mad, and doomed to babble about a half-remembered reckoning.
- Happy Accidents had Vincent D'Onofrio's character suffer from R.T.D.S. "Residual Temporal Drag Syndrome"
- The Terminator had Kyle Reese exhausted and disoriented after his time jump. The Terminator was a machine so it didn't suffer the same problems.
- Occurs in Primer:
- The time machine works by enclosing an area — usually a coffin-sized box — in a field for a certain amount of time, causing that area to Time Loop. Trying to walk in or out while the field is still on tends to mess up your anatomy, and you can't exactly wait until the field is completely off; all you can do is wait until the field has almost died and then get in. This leads to problems the more times the characters try it: one abruptly starts bleeding from the ears, and their once-normal handwriting devolves into The Illegible.
- Since this is essentially taking The Slow Path in the other direction, failing to pack enough air, food, and water is dangerous as well.
- It's possible that there are negative effects when two time travelers get close to each other, too.
- The Tomorrow Man involves a blue-collar worker from the 1970s who accidentally gets jumped into the 1990s. First time through, his stomach has an unpleasant reaction.
- In Paradox, the prototype time machine causes disorientation, nosebleeds and a persistent feeling of being unwell. Its chief architect actually knows it causes brain damage, but he considers his companions expendable for the cause.
- Predestination. People unused to time jumping feel ill, and John has to be hospitalised when the Bartender takes him on a particularly long jump to the future. Temporal agents are warned that making too many jumps can lead to psychosis. When the Bartender finally catches the Fizzle Bomber, he's revealed to be an insane future version of himself who claims to be working for The Needs of the Many, but the audience is left to wonder if that's true or just his delusion.
- In Michael Crichton's novel Timeline, some characters suffer "transcription errors", which accumulate with multiple travels, causing insanity and death.
- In Michael Moorcock's Behold The Man the time traveler has a pretty rough voyage and emerges nauseous. That's nothing to what's about to happen to him, though.
- Hellrides in Roger Zelazny's The Chronicles of Amber series were massively debilitating, involving the equivalents of jet lag and motion sickness as well as exhaustion. They're more dimensional travel than strictly time travel, but the concept is the same.
- One could also take a safe, comfortable trip called the "royal road." Hope you don't have anywhere you have to be at any particular time.
- The Stainless Steel Rat: This is an element of time travel in series.
- In the Haruhi Suzumiya novels people always keep their eyes closed when traveling through time. Open your eyes, and you risk seeing something so horrible that you'll end up puking for weeks.
- In Connie Willis' book To Say Nothing of the Dog characters routinely suffer from what is referred to as "time-lag", the effects of which usually last for several days, and consists of physical and mental disorientation; much like a more potent form of jet-lag or a hang-over. This is nicely portrayed when a nurse gives the protagonist a postcard of Oxford. When he rhapsodises over the dreaming spires she diagnoses serious time-lag. Also it allows the characters to carry the idiot ball.
- In Diana Gabaldon's Outlander series, time travel is potentially fatal - and the risk is cumulative, so that each trip is more dangerous than the last. None of the characters have made more than three time-jumps so far. Carrying large precious stones makes it safer and less unpleasant, to some extent, but the gems are consumed during the trip. (The ability to time-travel at all is also a trait only some people have, and is apparently genetically transmitted.)
- Dark (2017): Adam is Covered with Scars as a result of frequent trips across time. Other characters travel through time with no injury, but they seem to be using safer ways. Adam's only method is a time machine that he spends years desperately trying to repair without fully understanding how it works. His flawed attempts leave a mark, but he keeps trying.
- Doctor Who: Time travel without a capsule (such as a TARDIS or other time ship) is possible but not recommended due to the temporal sickness it causes. The effects are not explicitly stated, but appear to be similar to being put through a huge tumble dryer.
- When Rose encouraged the Ninth Doctor to allow Adam to travel with them, he got sick. Probably used as a device to highlight how useless he was in comparison with Rose.
The Doctor: He's your boyfriend!
Rose: Not any more!
- Jack managed to travel to the end of the universe while outside the TARDIS... but it killed him. (He got better, though.)
- The novel "Only Human" claims that using an unshielded Time Machine can result in the person being able to make only one trip. While the person feels no ill effects from that one trip, a second trip results in painful disintegration. This applies even if the second trip is in a "proper" time ship like the TARDIS. This is why the Neanderthal from the novel ends up staying in the 21st century. Of course, the reason the other time machine is unshielded is because it's steam-powered.
- In Goodnight Sweetheart, the only complaint Gary Sparrow has is wanting to know why time travel gives him gas?!
- Legends of Tomorrow depicts time travel as a very stressful experience with several possible side-effects depending upon the person and length of the jump. These include nausea, vertigo, temporary blindness, vomiting, aphasia...
Snart: Fine feel I.
- In seasons 4 and 5 of Lost, characters who travel in time (whether physically or mentally) suffer nosebleeds, lose their memories, and die of brain aneurysms.
- The Outer Limits (1995):
- In "A Stitch in Time", it is caused not by the act of time travel itself but by the alteration of history. Whenever an alternate timeline is created, the time traveler remembers both the previous timeline and the new one. Travelling through time and killing 20 future serial killers, creating an alternate timeline on each occasion, takes a serious toll on Dr. Theresa Givens' health and she has a cerebral hemorrhage. Although it is not fatal, she realizes that she does not have long left.
- In "Breaking Point", Andrew McLaren travels two days forward in time and back again. He begins to experience nosebleeds and severe jolts of pain and his behavior becomes highly erratic.
- In Seven Days, Frank Parker is the only living chrononaut; his survival is attributed to his unusually high tolerance for pain.
- In Sisyphus: The Myth, time-travelers are 'unstable' when they first arrive in the past for a few days/weeks. In some cases, they never stabilize and might phase out of existence completely. Moreover, there is a drug that can amplify the effects of this instability to torture and/or kill time-travelers.
- In Star Trek: Discovery, the only one to experience negative side effects after the ship's jump 930 years into the future is Georgiou. When Culber consults Kovich, the strange bespectacled guy at Starfleet Headquarters, he explains that it's a result of time travel coupled with dimensional travel. Since Georgiou is originally from the Mirror Universe, which has diverged from the Prime universe in the intervening centuries, Georgiou's atoms keep alternatively pulling her back in time and across dimensions. Kovich demonstrates the hologram of another such victim, who seems to have crossed over from the Kelvin timeline as well as the past.
- In the Star Trek: Voyager episode "Relativity", repeated use of time travel causes the user to become progressively ill, to the point of being fatal in certain circumstances. One version of Seven is killed this way, forcing the agents to recruit a past!Seven to fill the gap.
- In an interesting version in the episode "Blink of an Eye", there is a planet Voyager is orbiting that rotates approximately 83,000 times faster than Earth. When two astronauts from the planet visit Voyager, they are severely sickened by the differential between the passage of time. One doesn't make it.
- In the Star Trek: The Original Series episode "All Our Yesterdays", inhabitants of a planet are sent back to their past to escape their star going nova. Kirk, Spock and Bones travel without being given the necessary treatment, and will die if they don't get back to the present within a few hours. On the other hand, anyone who has been given the treatment to travel to the past cannot return to their own time without instantly dying. For those who went through to escape the supernova, this is a moot point anyway, but at an unspecified point in the planet's past, it was used in other ways, including by a dictator to send enemies into permanent and inescapable exile.
- Intriguingly, Terminator: The Sarah Connor Chronicles has characters exhibit virtually the same ill effects post time travel as in To Say Nothing of the Dog as cited above. John Connor even goes so far as to start referring to it by the same term, "time-lag". Makes you wonder...
- Time Trax: Darien Lambert can't return to the year 2193 until he finds and sends back all of the fugitive criminals from his time. This is because time travel requires the traveler to be injected with a drug called TXP, which is usually fatal if administered more than twice (although, one person is confirmed to having survived a third dose, although he is disfigured by the attempt). Lambert was dosed with it when he was sent to 1993; returning to 2193 will require a second dose, after which he can never travel through time again. In one episode, under the influence of a Mad Scientist's device, he admits that he occasionally thinks to just forget it all and go back home. SELMA responds that no one would blame him if he did. After all, they can always send someone else in his place.
- The Twilight Zone (1985): In "One Life, Furnished in Early Poverty", Gus Rosenthal begins feeling weak soon after he is transported back in time to the 1940s. After several days, he realizes that he has to return to his own time or he will die.
- Timesickness (a.k.a. "The Crosstime Cookie Toss") is a common disadvantage in GURPS Time Travel.
- In Achron, units glow softly right after you chronoport them. They're perfectly functional, with the one exception being that they cannot chronoport again until the effect wears off. The effect has thus earned the nickname "rechronoport delay".
- Porky in Mother 3 combines this with Age Without Youth (sort of) and Immortality Immorality.
- In TimeShift it is suggested that time travel may cause disorientation and even memory lost. The Beta suit does counteract some problems, but judging by the intro video motion sickness may be a concern. The player character also passes out shortly after a time jump.
- This can be a side effect of the "tears" in Bioshock Infinite. The severity of the sickness depends on how well people can cope with it, and people who died in other timelines have it much worse.
- The Chrono Legionnaire unit in Command & Conquer: Red Alert 2 is able to teleport anywhere on the map using the Time Machine technology invented by Albert Einstein (i.e. it's still, technically Time Travel, minus the "time" part). The farther the jump, the longer the unit has to spend "shifted". While in this state, the unit can't do anything but can be attacked and destroyed. Strangely, the cut scenes showing people using the Chronosphere for actual time travel has no ill effects (beyond the fact that touching someone in the past results in that person ceasing to exist).
- Resetting your turn in Into the Breach may cause one of your pilots to complain about the headaches travelling in time gives them.
- Both played straight and averted in Cwen's Quest. Travelling forward in time is painful and draining, but when you go backwards it actually has the opposite effect and temporarily gives you super powers.
- Both averted and played straight in Autumn Bay. When Andrew and Marie-Ange are sent to the Bad Future by Nesariel, they are just fine. In fact, they take the whole thing in stride. On the other hand, after being sent back to their home time by Dr. Deacon, they are quite stunned upon their return.