Unsuspectingly Soused

"Cecile: This sure doesn't taste like an iced tea. Sebastian: It's from Long Island."

- Cruel Intentions

Someone drinks a drink he or she expects to have little, if any, alcohol. Instead, it turns out to be not only alcoholic, but very much so, resulting in the character getting plastered.

This is Truth in Television, as some cocktails are formulated to minimize the alcohol flavor and can thereby catch an unsuspecting drinker off-guard.

But Liquor Is Quicker is this trope invoked by an unscrupulous suitor. I Drank What? occurs when the drinker imbibes something not meant for human consumption at all, though a teetotaler might have this reaction when learning what's in the drink.

Related to Intoxication Ensues.

Anime and Manga

 * The Full Metal Panic!: The Second Raid OVA had Tessa popping by Mao's quarters for a chat where Mao gave her something to drink. Cue next shot of Tessa lying on the couch passed out. Mao confessed the next day that the can contained alcohol which resulted in Tessa giving her an earful, doubly justified: not only is Tessa underage, she also happens to be Mao's superior officer (though the only stated reason was "alcohol destroys brain cells").
 * In Naruto, this has happened to Rock Lee at least three times that we know of. It's never a good thing - especially since.
 * Negima: Negi gets this when he mistakenly is given sake. As Nitta put it, "Oh no, the crying begins."
 * In the first So Ra No Wo To OVA, the whole platoon gets drunk on spiked tea, with only the resident straight-man girl avoiding the effects (to her dismay).
 * In Vision of Escaflowne, Hitomi imbibes a pink liquid at a dinner... which turns out to be some kind of liquor, and she gets very drunk.
 * Sort of happened to Belldandy once in Ah! My Goddess. Of course, what she was drinking wasn't alcoholic at all (She had already consumed enough sake to drink everyone else at the party under the table without even getting buzzed) - it was cola.

Comic Books
"Woman from Galactic Temperance society: Surely you don't think I'll be letting you drink alcohol. Buck: It's milk. Woman from Galactic Temperance society: What do you take me ... (Sips from glass) Why, it is milk. (Eyes dilate and she collapses) Buck: Vrang Beast milk? Al: Vrang Beast milk. Buck: 150 proof? Al: Only type I serve!"
 * Shows up in the second Buck Godot: Zap Gun for Hire story.

Film

 * This trope turns up in a couple Buster Keaton movies.
 * In the short "Hard Luck," Buster chugs a bottle labeled "POISON" which is actually whisky.
 * In the feature Three Ages, Buster is at one point unaware that he's imbibing someone else's discreetly disposed of drink.
 * Dumbo accidentally drinks champagne when a bottle of it falls in his water bucket. How one gets drunk enough on diluted champagne to see pink elephants is beyond me. On the one hand, he's a child and it's a full bottle of champagne. On the other hand... he's an elephant.
 * The Laurel and Hardy short Them Thar Hills had the pair taking a trailer out to the country, camping out at a cabin that had just been vacated by moonshiners who poured their liquor down the well while fleeing revenue agents. While Stan and Ollie enjoy the mountain water, a stranded motorist leaves his wife there while he hikes for gas. Coming back he finds the three of them whooping drunk - Hilarity Ensues.
 * Yours, Mine, and Ours has a scene where Helen comes over to meet Frank's children, and orders a light screwdriver. Three of his sons, wanting to play a joke on her, spike her drink with extra alcohol, without knowing that each other is doing so. She becomes extremely drunk in the next scene, and Frank later comments that she was lucky she didn't die from such a concoction.
 * Poison Ivy: The New Seduction. The villainess spikes a non-alcoholic drink with alcohol to make her targeted victims drunk. Then one of the victims adds even more alcohol without knowing the drink is already spiked. Both of the victims end up bombed out of their skulls.

Literature

 * In Anne of Green Gables, Anne gives her friend Diana what she thinks is Raspberry Cordial. Anne herself doesn't drink it, so she doesn't realize Diana's been chugging currant wine.
 * Discworld:
 * Subverted in Witches Abroad. The witches are drinking absinthe, because Magrat recognizes the name as meaning wormwood and thinks it's a herbal drink. Afterwards Granny Weatherwax says "I'm sure there was alcohol in that. I definitely felt a bit woozy after the third glass."
 * Played straight in The Last Continent, when Rincewind downs several Ecksian beers in quick succession. He'd assumed that its clarity meant it couldn't possibly be as strong as Ankh-Morpork beer, and was 100% wrong.
 * In the novel A Kiss in Time, a princess who's just arrived from the 18th century goes to a party and doesn't realize that Jello shots are alcoholic.
 * In Douglas Reeman's A Prayer for the Ship, about Royal Navy torpedo boats in World War II, a subordinate slips something "high-octane" into the squadron commander's drink. The commander then goes around to all the squadron's boats to tell them how proud he is of the job he did turning them into an effective fighting unit. He gives them enough credit, though, that the main character suspects the sailors will actually respect the commander more for this humanizing lapse.

Live-Action TV
"Kurt: (Slurring) Oh Bambi... I cried so hard when those hunters shot your mommy."
 * A bizarre use in Angel, Fred and Wesley end up totally drunk. After realizing this they consider how much alcohol they've actually consumed: zero and a third of a half a beer respectively. It turns out that Lorne's powers have temporarily transformed him into a Reality Warper and earlier he told them that it's a party, they should be drunk.
 * Inverted twice on Arrested Development. Maebe ordered several virgin versions of alcoholic drinks, without realizing what the prefix actually means. Later she and George Michael drink from wine bottles that GOB has switched with something non-alcoholic in to a botched attempt to copy Jesus' water-into-wine trick.
 * Bones does this with a quasi-Noodle Incident: it's implied that Hodgins and Zack had spiked the eggnog with (presumably very high-proof) alcohol they distilled in their lab at the previous year's Jeffersonian Christmas Party, and that an embarrassing form of this was the result. Of course, it's a Noodle Incident, so exactly what happened is unclear.
 * Of course, what the eggnog was doing without high-proof alcohol in the first place is beyond me. Quoth Alton Brown: Eggnog requires bourbon (or if you can't find it/don't like it, Scotch or rye), to kill what few bacteria remain from the raw eggs you used to make the eggnog. (If you have teetotalers/designated drivers wishing to participate in the festive spirit, you have a separate bowl, made with inferior but much safer pasteurized eggs, for that purpose).
 * One episode of Get Smart had a KAOS agent (a master of disguise) pretending to be the Chief, with some...entertaining...results when he and the real chief were both in Smart's apartment at the same time. The two confusing buttermilk and brandy scenes (one Chief asks both Smart and 99 independently for a glass of buttermilk to settle his stomach, the other asks both independently for a glass of brandy to settle his nerves, and the one that asked for buttermilk keeps getting brandy).
 * I Love Lucy: Vitameatavegimin.
 * Taken (comically) to the max in an episode of M*A*S*H, when Hawkeye and company trick Frank into consuming so much alcohol he passes out.
 * Monk, who drinks one sip of alcohol (specifically wine) once a year on his wedding anniversary, once ordered a bottle of non-alcoholic claret so he could appear to drink while talking to someone he suspected to be a murderer. As it happened, he ended up with regular old alcoholic claret and downed it all straight from the bottle. Hilarity, of course, ensued. "All these people are crinimals. They're crinimals."
 * Neighbours had an episode where someone made a highly potent cocktail that he decided looked and tasted exactly like a smoothie - and downed it, with predictable consequences.
 * An episode of Night Court had Christine drinking what she thought were iced teas, but were in fact Long Island iced teas. She ends up running into a door.
 * Donna on That '70s Show drank a Long Island Iced Tea thinking it was non-alcoholic.
 * On Glee, April Rhodes tries to get on Kurt's good side by giving him crantinis (and vintage muscle mags) by telling him that they'll give him all the courage he needs. He doesn't seem to realize what he's drinking, although he learned enough by the end of the episode to become one of the only two non-drinkers in Glee.


 * On Parks and Recreation, everyone drinks Tom's "Snake Juice", which turns out to be 140 proof alcohol and highly caffeinated, leading to a montage of everyone totally drunk and crazy.
 * In an episode of Campion, the title character is made very drunk in an attempt to murder him. His enemy treats him to a sherry, then invites him to dinner and orders a magnificent wine—but neglects to mention that all alcohol must be out of the system before trying it. We are treated to several minutes of Campion reeling around London, laughing wildly, before he is pushed in front of a train.
 * On an episode of Hustle, Sean is deliberately not drinking after nearly screwing up a con by being drunk. However, the mark spikes his orange juice with vodka, resulting in him getting drunk again.
 * F Troop had an episode where the tee-totaling Captain Parmenter is persuaded to take a cure for his cold that has a little alcohol in it, unaware that several members of his troop have innocently attempted to help him get better by secretly adding their own alcohol-based cures to the pot as well. This results in a completely soused Parmenter yelling "Happy New Year!" at Fort Courage's infamous cannon before setting it off himself in the traditional fashion.

Theatre

 * Guys and Dolls. Dulce de Leche has alcohol in it? "Only enough to act as a preservative," says Sky, but by then he's got Sarah already hooked.
 * Fridge Brilliance: Enough alcohol to preserve or purify liquid is enough to get you hammered.

Video Games

 * In Grand Theft Auto IV, Niko can take one of the early girlfriends, Michelle, out on a date to a bar, and will invariably emerge absolutely twunted, commenting that the drinks were a lot stronger than he'd usually expect, with Michelle by contrast being stone cold sober.

Web Comics

 * One time in Sabrina Online has Sabrina and Zig-Zag head out to a bar and Sabrina chugs down a number of Kahluas before realizing that the ones she normally drinks from the store have a lowered alcohol content than the one she has. The initial reaction suggests trouble, but fortunately, she's more of a silly and sleepy drunk.
 * In Tales of the Questor, Quentyn Quinn and his friends get horrendously plastered on blackberry sherry, which is considered to be lightly alcoholic. It turns out that it was homebrewed blackberry BRANDY and packed "enough whallop to knock a troll flat".
 * Archipelago: Riley recounts a time when Tuff was given medicine with alcohol in it. The results...were hilarious. (except to Tuff)
 * Happens again to Tuff in book 6. This time, it's intentionally being used against him.

Western Animation

 * Marge Simpson gets drunk from too much punch on the nuclear plant employee picnic. She's already had a few drinks before suspecting "there's a little bit of alkeyhol in this punch".
 * In a later episode, she fell victim to the aforementioned Long Island Iced Tea.
 * Later, Bart spikes Mrs. Krabappel's coffee with alcohol to get her to mellow out. It did get her drunk...and fired.

Real Life

 * Truth in Television, and also goes for lots of frozen or blended drinks. Daiquiris, pina coladas, frozen mudslides and the like are all notorious for containing large amounts of alcohol, the taste of which is covered by ice cream, fruit puree, chocolate or some combination thereof. The drinker isn't apt to notice just how much they've had until they've gotten themselves well and truly loaded.
 * Rum&Coke drinks have this effect on a large number of people. The taste won't give it away, but most glasses contain a full serving of rum.
 * Often happens to those who are suckered into drinking Long Island Iced Tea thinking it's nonalcoholic.
 * Although this is probably a bit overstated in fiction. A Long Island Iced Tea being one of the most alcoholic commonly-served mixed drinks (at least in America), it's highly unlikely that someone wouldn't notice the high alcohol content after the first sip, particularly if they're an infrequent enough drinker (or, you know, have never seen this joke before) that they wouldn't know what one is.
 * According to some older history books on the Middle Ages, a nobleman kept white wine on hand to "water" the drinks of guests who didn't want to drink full-strength (red) wine, and got a bishop's entire entourage totally sloshed this way. It's anyone's guess whether this really happened or if it was a cautionary tale mistaken for truth.
 * Often happens when people drink on airplanes or just before getting on one, due to the altitude.