History Main / OneDoseFitsAll

A sub-trope of ArtisticLicenseMedicine, ArtisticLicenseBiology, and ArtisticLicensePharmacology. See also InstantSedation, TranquillizerDart, KnockOutGas, DeadlyGas, SlippingAMickey, and TamperingWithFoodAndDrink. Frequently applies, even more illogically, to the HealingHerb. If the same drug affects people the same way despite differences in species (including, for example, humans and aliens in SpeculativeFiction works), this trope overlaps with NoBiochemicalBarriers. For a more violent and equally unrealistic means of rendering someone unconscious, see TapOnTheHead.

* Played straight throughout the ''VideoGame/{{Hitman}}'' series. Any poison or sedative administered to any NPC will be equally effective on any of them. Sedating an NPC with a given amount of chloroform will knock them out for a fixed period of time, regardless of whether they are a petite woman or a burly Russian gangster. There is also at least one instance in which a possible means to assassinate two targets is to serve them the same poisoned drink near-simultaneously, following which they both drop dead within seconds of each other despite their different sizes.

* ''WesternAnimation/DanVs'': When Elise has Chris dress up as Dan in "[[Recap/DanVsS1E4DanVsTheNinja Dan Vs. the Ninja]]", she points out how a dose of poison meant to kill Dan won't kill the much taller and larger Chris.

* ''VideoGame/{{Pokemon}}'': The 'poisoned' status (and its nastier 'badly poisoned' cousin) deals a fixed amount of the victim's maximum {{Hit Point}}s every round. This means that, ignoring any other sources of hit point loss, any poisoning attack will defeat any two pokemon just as quickly (provided they are not immune to it). [[TacticalRockPaperScissors Even pokemon that resist (i.e. take half damage from) attacks of the poison type]] still take the same amount of damage from the 'poisoned' status, though Steel types NoSell both poison damage and the 'poisoned' status.

[[caption-width-right:300:You'd think a dart big enough to incapacitate a bear would kill Barney, [[TheAlcoholic but then you'd be underestimating the amount of practice his liver has had]].]]

* ''WesternAnimation/DanVs'': When Elise has Chris dress up as Dan in "The Ninja", she points out how a dose of poison meant to kill Dan won't kill the much taller and larger Chris.
* ''WesternAnimation/TheSimpsons'': As a bear wanders through Springfield in "Much Apu About Nothing", Chief Wiggum tries to shoot it with a tranquilizer dart. The first shot hits Barney instead, while the second shot connects. Both Barney and the bear react the same (despite the differences in time of administration, body mass, constitution and ''species''), and there is no indication that the tranq shot into Barney gave him any long-term ill effects. Then again, this ''is'' [[TheAlcoholic Barney]] we're talking about; mere tranquilizers are nothing compared to what he puts his liver through on a regular basis. In fact, he only succumbs after he pulls out the dart, breaks it in half, and ''[[UndiscriminatingAddict drinks the contents]]''.

* ''WesternAnimation/BatmanTheAnimatedSeries:'' Averted in "Pretty Poison". Poison Ivy's toxic kiss puts Harvey Dent into a coma, but only somewhat impairs Batman. Justified in that Batman got a smaller dose (unlike Harvey, he knew the danger, so he did his best to resist the kiss and started spitting immediately afterwards) and is in prime physical condition.

* This trope was tragically Averted in the 2002 Moscow theater hostage crisis. To subdue terrorists who had taken over the theater and who were holding over 800 people hostage, authorities pumped an undisclosed KnockoutGas in through the ventilation system. The gas worked, but killed at least 170 people, including both terrorists and hostages. It may have even killed more.

* Averted in ''VideoGame/JurassicPark'' for the Sega Genesis: different dinosaurs not only take different numbers of tranquilizer darts to knock them out, they also stay unconscious for different lengths of time. A compy only takes one dart to put under and will stay asleep for a long time. A Dilophosaurus takes more darts and stays asleep for a moderate amount of time. You can technically render the T-Rex unconscious if you dart her enough times, but it takes an ''enormous'' number of darts and is unlikely to last long enough for Grant to safely run past her. Played straight with grenades, though: a gas grenade will render any dinosaur unconscious and they'll stay out for roughly the same amount of time.

This trope refers to those FridgeLogic-y moments in which a poison (or sedative, tranquillizer, medicine etc.) is administered to several different people and takes effect on all of them after roughly the same period of time and with the same effects, despite differences in body mass, how much of the substance was administered and constitution. Sometimes the people affected are even of different species, such as a poison simultaneously administered to both an adult male and a dog, who nonetheless react identically to any poison administered.[[note]]Considering the [[https://www.battersea.org.uk/pet-advice/dog-care-advice/toxic-food-dogs laundry list of substances]] which are perfectly safe for humans to eat but toxic for canines, even banal examples of this type ''do'' strain credibility.[[/note]] Supposing that, in our example above, Bob is a human whereas Carol is a three-headed Martian whose species evolved under entirely different circumstances to our own; how could we possibly expect Carol to react in the same way as Bob to being poisoned (sedated, etc.)?

'''Note:''' The key element of this trope is that it shows the same substance affecting ''more than one entity'' (human, animal, alien etc.) in the same way, even if it logically shouldn't (because of differences in dosage, body mass, constitution, species, etc.). If you have an example of a poison or sedative, etc., affecting just ''one'' individual, it's not this trope.

* Averted in ''[[https://www.fanfiction.net/s/10541324/9/First-Knight First Knight.]]'' Xander mentions having a single dose of the antidote to the poison used in the lobster [[ItMakesSenseInContext at a dinner set in the 1930s]] because he didn't expect to take anyone else back with him. However, he explains that the dose is tailored for his weight and metabolism; he could use a smaller amount if Willow or Dawn got poisoned, but has no idea how to account for a Slayer's constitution and metabolism. As a result, he can't do anything to save the poisoned alternate Xander and Faith they meet.

* The climactic trick in ''Film/TheIncredibleBurtWonderstone'' can only work if this applies on a massive scale with near-perfect simultaneity. Even worse, it has to apply to both onset ''and'' recovery because [[spoiler:anyone who resists the gas even slightly to either stay awake a little longer than average or wake up a little sooner than average will notice that people around them are sleeping, which would be a pretty big tip-off]]. Of course, it's a comedy, so RuleOfFunny is in full effect and [[MST3KMantra we're not supposed to worry about that]].
* In ''Film/DrNo'', Bond and Honey both pass out from drugged coffee provided by the villain. Honey does feel the effects first, but only by a few seconds despite being much smaller than Bond. Strangely, there were already captured and no real explanation for why they were drugged is given.

* ''Literature/DannyTheChampionOfTheWorld'': Danny believes this, and it makes him slightly worried; his big plan hinges on being able to drug two hundred pheasants with fifty sleeping pills. His father points out that a pheasant is only a fraction of the size of a man, so if a pill can put a man to sleep, a quarter of a sleeping pill will be more than enough to knock out a pheasant. [[spoiler: They had not accounted for the sleeping pills wearing off the following morning, when most of the pheasants wake up. However, six of them do not wake at all, presumably because they had taken more pills than the others.]]
* In ''Literature/OneHundredYearsAhead'', a dose of soporific gas from Rat's gun, intended for Alice (a slim eleven-year-old), instead hits Jolly U (an adult FatBastard weighing 150 kg) and [[InstantSedation immediately puts him to sleep]]. However, it’s made clear that the pirates are trying to kidnap rather than kill Alice (while realistically, a dose that instantly knocked off Jolly U would have likely been fatal for her), making it an example to the trope.
* In ''Literature/SmallFavor'', it gets discussed that this ''doesn't'' apply. A group of Denarians have a plan to capture Ivy, current host of The Archive, and includes the use of an airborne sedative. Once Harry realizes that it's being used- especially since he starts feeling the effects of it himself- he starts trying to get to Ivy's location to make an escape, since she will be knocked out before he is. Also, one Denarian feels the need to remind some of the others that this part of their plan depends on the fact that Ivy is (still) a child. Harry himself is a tall ("NBA sized") adult.
* In ''Literature/TheWitches'', the hero and his grandmother turn all the witches of England into mice, with five hundred doses of Delayed Action Mouse Maker, which they reason will give all two hundred witches a double dose at least. The hero plans to put the Mouse Maker into their food while it is being prepared in the kitchen, and worries that the wrong guests might receive it. His grandmother tells him to listen carefully to what the cooks are saying, and hand waves the problem of other guests eating the same food by telling him that for a big party, the food is prepared separately. In spite of knowing that giving more than one dose will make the delayed action unpredictable, the witches all turn into mice at the same time.

* On ''Series/{{Zoo}}'', the same tranquilizer darts which take down a brown bear via InstantSedation are also used on big cats less than half its size, and a German shepherd which couldn't have weighed even 1/10 of what the bear did.

** One episode featured a man drugging people with an opiate so that he could frame them for home invasions. While he doesn't particularly care if the drug kills them, they all survive long enough for him to shoot them at the crime scene. Except for one, who was an opiate addict and built up a tolerance, therefore recovered more quickly and managed to escape. But we don't know how he dosed them or how long the drug took take effect (the one survivor was overpowered, drugged, and locked in a trunk for a few hours, so it's possible that process was to ensure the drug had time to kick in).

** Yet another episode featured an unsub keeping women drugged ([[AndIMustScream immobile but conscious]]). The episode claims the unsub has some medical training, but considering that "training" comes from [[spoiler: being the daughter of a psychiatrist who submitted her to electroshock therapy to stop her from revealing he'd molested her]], that barely explains how they got ''access'' to the drugs and equipment, much less the understanding to properly use them. While the victims did turn up dead, that wasn't a problem of dosage, just a matter of their brains basically giving up without the proper mixture of stimulus and response. The one SpannerInTheWorks turned out to be a victim who was diabetic, which somehow allowed her to process the drugs more quickly. At the very least, the women were all chosen based on their bodytype, so they were all consistently petite.

* In the second season of ''Series/{{Hannibal}}'', there is a serial killer that kills his victims with heroin overdoses after [[MadArtist stitching them into a human mural]]. However, one victim averts this trope due to being a former addict, allowing them to survive the dosage and revive later, able to flee and almost escape.

* Zig-zagged in ''TabletopGame/{{Shadowrun}}'': drugs, toxins, and other chemicals affect every character equally with the same nebulous quantity of a single dose, whether it be an ordinary human, an ork built like a pro linebacker, or a two-and-a-half meter, three-hundred kilogram troll. The only concession made for different body sizes is that the subject's Body attribute reduces the duration of the effect to a minimum specified in the chemical's description; the troll ''will'' fall asleep when laës'd, even if it's the same size dose as the human got, but he'll wake up sooner and remember more.
* Zig-zagged in ''TabletopGame/DungeonsAndDragons'' 3.5 and other D20 tabletop games where poisons come in fixed doses and require Fortitude saves to resist and successfully eliminate, and Fortitude varies depending on Constitution, class levels and racial hit dice (sometimes bigger creatures have higher Constitution, but not always). Poisons are for the most part "save or suck"; you either successfully resist and are unaffected or you suffer the full effect, making them a bit of a gamble and somewhat inconsistent.

* Its sister series ''TabletopGame/{{Starfinder}}'' is a bit worse at it, as poisons are individually saved for even if multiple doses are given. As for body size, any dosage affects most races equally, whether small or large. There's even a whole class (the Biohacker) that's centered around injecting custom doses into allies and enemies, though at least they have the excuse that [[{{Nanomachines}} nanites are involved]].

** Zig-zagged in ''VideoGame/MetalGearSolid2SonsOfLiberty'', due to GameplayAndStorySegregation. This game is the first in the series to feature tranquillizer-firing weapons, with which enemies can be dispatched non-lethally. Tranquillizer darts will be equally effective on any regular enemy regardless of size (only location of the shot makes any effect - a guard will feel the prick of the dart and try to find where it came from for a few seconds before falling unconscious if he's shot in the hand, but a dart to the head is instant sedation), provided they are not wearing full body armour, making this a straight example. In boss fights, however, it's played with. Bosses can also be defeated non-lethally, but rather than knocking them out with a single dart to the head, they instead have a "stamina" bar (much like their regular health meter) which depletes the more they get hit by tranquillizer darts. However, this stamina bar is based not on the enemy's size, physical fitness or constitution, but rather simply scales up linearly as part of the game's difficulty curve. So it's averted, but in the interests of gameplay rather than realism (could be considered an AcceptableBreakFromReality, as the boss fights would be very anticlimactic if the bosses reacted to tranquillizer darts the same way the regular enemies do).

* The tranquilizer rifle in ''VideoGame/FarCry2'' takes it to absurd lengths, as whatever kind of tranquilizer and dosage it's using is enough to instantly ''kill'' any enemy you shoot with it, regardless of size or shot location. However any hit that isn't in the head the victim will scream before dying while a headshot is instant, silent death.
* ''Videogame/DwarfFortress'' has the option to give an individual venom this feature. Taking existing game creatures as an example: Giant Cave Spider venom (which causes paralysis) averts this, and behaves realistically in that its effects depend on mass. Therefore, its bite will paralyze a dwarf to the point they'll asphyxiate and die, but a dragon will only feel mildly numb, and possibly be inconvenienced after multiple bites. On the other hand, Giant Desert Scorpion (a neurotoxin, or the closest the game can manage) venom plays it straight: Its sting will, eventually, kill a dwarf, a dog or a dragon in the same amount of time, by way of making their entire nervous system (brain including) necrotize and rot away.

* Averted in ''VideoGame/JurassicPark'' for the Sega Genesis: different dinosaurs not only take different numbers of tranquilizer darts to knock them out, they also stay unconscious for different lengths of time. A compy only takes one dart to put under and will stay asleep for a long time. A Dilophosaurus takes more darts and stays asleep a moderate amount of time. You can technically render the T-Rex unconscious if you dart her enough times, but it takes an ''enormous'' number of darts and is unlikely to last long enough for Grant to safely run past her. Played straight with grenades, though: a gas grenade will render any dinosaur unconscious and they'll stay out for roughly the same amount of time.

* ''VideoGame/HiddenExpeditionTheCurseOfMithridates'': After a too dumb to live NPC sets off a hidden booby trap, your character must collect the three rarest items of the antidote's twenty-seven ingredients. After you're successful (of course), the vial with the liquid -presumably a suspension, since most of the ingredients were solid is... put into a machine that splits the liquid into an equal number of doses and sends them through some very long tubes to the patients' [=IVs=]. Did we mention that two of the three ingredients are the last of their kind and can never be found again? So if this fouled up, there was only maintenance care and the hope they'd beat the poison themselves to fall back on?

-->"I’m tempted to say Harem’s hypospray uses M99, same as Series/{{Dexter}}, since it’s extremely powerful and just as importantly, the antidote is nearly instantaneous, but reading up on it, it sounds so dangerous that I imagine Arc-SWAT would have something less risky. Still if they’re being constantly monitored by the wristband, maybe it’s a reasonable use case."

* This is partly why sharing prescription medication is a bad idea. A dosage that works for one person may not work for another. Or in more serious cases, the same dosage may even harm or kill another. Besides, one should always consult a doctor before starting any new medication. Not only is it safer but it's also legal, so you won't get sent to jail.

* In ''Literature/TheWitches'', the hero and his grandmother turn all the witches of England into mice, with five hundred doses of Delayed Action Mouse Maker, which they reason will give all two hundred witches a double dose at least. The hero plans to put the Mouse Maker into their food while it is being prepared in the kitchen, and worries that the wrong guests might receive it. His grandmother tells him to listen carefully to what the cooks are saying, and hand waves the problem of other guests eating the same food by telling him that for a big party, the food is prepared separately. In spite of knowing that giving more than one dose will make the delayed action unpredictable, , the witches all turn into mice at the same time.

* ''Literature/DannyTheChampionOfTheWorld'': Danny believes this, and it makes him slightly worried; his big plan hinges on being able to drug two hundred pheasants with fifty sleeping pills. His father points out that a pheasant is only a fraction of the size of a man, so if a pill can put a man to sleep, a quarter of a sleeping pill will be more than enough to knock out a pheasant.