[[quoteright:300:http://static.tvtropes.org/pmwiki/pub/images/art-353-tandberg-kennett-300x0_1356.jpg]]
[[caption-width-right:300:Jeff Kennett, former [[AustralianPolitics Victorian premier]] and [[AustralianRulesFootball Hawthorn Football Club president]], as depicted by Ron Tandberg]]

A character with a big mouth says something stupid or, better yet, self-incriminating. Usually the twin trope to or immediately followed by DidIJustSayThatOutLoud.

The trope name comes from the phrase "to put your foot in your mouth" (also playfully referred to as "foot-in-mouth disease", a pun on the very serious livestock illness "foot-''and''-mouth disease").[[note]]Which in turn is not to be confused with the rather less serious [[http://en.wikipedia.org/wiki/Hand,_foot_and_mouth_disease hand, foot, and mouth disease]], which primarily afflicts small children and is generally speaking a week's nuisance at worst.[[/note]]

Closely related to IgnoreTheDisability.

Can lead to either ChangeTheUncomfortableSubject or DiggingYourselfDeeper. Sometimes both.
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!!Examples:

[[foldercontrol]]

[[folder: Anime and Manga ]]

* Tsurubami Kamome from ''Manga/MedakaBox'' actually gets kicked in the mouth '''twice''' for doing this too often. [[MadeOfIron Not that it hurts him]].
* CowboyBebop : "Open foot, insert mouth."
* [[NationsAsPeople Lat]][[FragileFlower via]] of ''AxisPowersHetalia'' is prone to this, which is a very bad thing when [[{{Yandere}} Russia]] is constantly hanging over your shoulder. Often closely followed by Lithuania or Estonia's "[[SayMyName Latviaaaaaaaaaaa]]!"
-->'''Latvia''': I do feel safer in his hairy arms.
-->'''Estonia''': [[LampshadeHanging You should really keep your mouth more closed]].

[[/folder]]

[[folder: Fanfiction ]]

* [[http://www.fanfiction.net/u/450594/elecktrum Elecktrum's]] Narnia Fics are full of this trope. One fic revolves around it completely, and another has a chapter revolving around the similar phrase "eating crow." Her [=OCs=] and minor characters also get into the act, especially where Edmund is concerned:
** Tumnus unintentionally insults Edmund by implying that Edmund had worked for the white witch in "The Conscience of the King".
** In "Black Dwarfs, Blue River" an overzealous faun angrily tells Edmund regarding the persecution of families of some satyrs who fought on the witch's side that the wives and children (who did not fight for the witch) were "Sons of traitors [who] deserve what what they get." Edmund responds cooly: "so what will you call my sons?" Oops.
** And then there's Ilano's RightInFrontOfMe moment in "They Also Serve"
* In the prequel to ''Fanfic/RespawnOfTheDead'', Heavy accidentally insults Medic a few times. But, to be fair, it's pretty clear that Medic is only insulted by being told he sounds like Greta Garbo because he has no idea he was practically quoting her.
* In ''Fanfic/KiraSweetheart'' Light has one of these moments [[spoiler: when he discovers that [[MoralityPet L]] has been abused in the past.]]
-->'''Light:''' WHO did this? Give me their name!
* The ''WesternAnimation/MyLittlePonyFriendshipIsMagic'' fanfic "[[http://www.fimfiction.net/story/71788/the-model-caretaker The Model Caretaker]]" Has Fleur de Lis struggle with this in the first half of the story, especially when Fluttershy is about.
* The ''FanFic/NewLookSeries'' has several examples of this trope.
** [[VideoGame/TheLegendOfZeldaOcarinaOfTime Young]] [[VideoGame/SuperSmashBros Link]] gets in trouble with Peach due to him pretending to be her, mockingly.
** [[Manga/RurouniKenshin Kenshin]] also gets in trouble when he tells Kaoru that he can't understand what Kaoru is going through right now because he isn't a woman like her.

[[/folder]]

[[folder: Film ]]

* In ''[[Film/ShortCircuit Short Circuit]]'' Howard theorizes the potential danger of having their laser-armed robot roaming free. The stereotypical Indian guy, Ben, hasn't really grasped the concept of discretion.
--> '''Howard:''' What if it decides to melt down a busload of nuns? How'd you like to write the headline on ''that'' one?
--> '''Ben:''' Nun Soup?

[[/folder]]

[[folder: Live Action TV ]]

* ''Series/BuffyTheVampireSlayer'': Spike does this often when he's trying to court Buffy..
** Invoked by Buffy in "Dopplegangland" when she tries to apologize to Willow (not realizing she is talking to Willow's [[EvilTwin alternate universe vampire double]]) for an unfortunate comment earlier in the episode, saying, "You know how my foot likes to live in my mouth."
* Referenced fairly often on ''Series/{{Mash}}''. In one case, BJ claims Charles has "put a whole shoe store" in his mouth." (That example, interestingly, was incorrect, as Charles had fully meant to offend everyone.)
* In ''{{Firefly}}'', Simon does it virtually every time he tries to have a conversation with Kaylee.
* ''{{Coupling}}'': A form of CannotTalkToWomen, by Jeff: just about every time [[ManChild Jeff]] talks to a woman, he manages to do this. [[http://www.imdb.com/character/ch0023361/quotes For example]], this exchange occurs just when things seem promising:
-->'''Lynda''': I like kissing, don't you?
-->'''Jeff''': Oh, yeah! Especially the tongues part. I love getting all that extra tongue. You know, sometimes I eat really cold ice cream just so that my tongue goes numb and it feels like someone else's... But then we all get lonely sometimes.
* In ''Series/{{Sherlock}}'', we have Molly.
-->'''Molly''': How's the hip?
-->'''Mrs. Hudson''': Oh, it's atrocious. But thanks for asking.
-->'''Molly''': I've seen much worse. But then I do [[{{Squick}} post-mortems]].
* ''Series/StarTrekTheNextGeneration'': During the 3rd season episode, ''Hollow Pursuits'', Capt. Picard accidentally calls Barclay by his unofficial nickname ''Broccoli''. Data tries to put a positive spin on the situation by referencing psychology but really only makes the situation worse.
* In one episode of ''Series/TheGoldenGirls,'' Blanche had an epic one. She meets and asks out a man she met in a bar, not realizing at the time (since he was sitting down) that he was blind. When he comes to pick her up for their date, she enters the room, saying things like, "Aren't I the prettiest thing you've ever seen?" and "What's the matter, ''are you blinded by my beauty''?" She finally takes a good look, sees his cane, and stops in her tracks. [[DeadpanSnarker Sophia]] directly addresses it, saying, "Want a glass of water to wash down your foot?"
* ''{{Series/JAG}}'': [[{{Characters/JAG}} Lt. Bud Roberts]] falls victim to this fairly often, especially in the pilot movie whenever dealing with Lt. Caitlin Pike. His case of Foot-in-Mouth Disease is particularly unfortunate given that his original job is Public Affairs.
* ''{{Series/NCIS}}'': [[{{Characters/NCIS}} Jimmy Palmer]] is very prone to this. He does not seem to have heard the old adage that "a closed mouth gathers no feet". His foot tasting episodes routinely escalate to DiggingYourselfDeeper territory.
* In ''Series/DoctorWho'', the Tenth Doctor has a bad habit of doing this while talking to [[spoiler: Queen Elizabeth I]], repeatedly saying terribly offensive or regrettable things under the assumption she was a zygon duplicate. It gets them ''[[spoiler: married]]''.
* ''Series/AMoodyChristmas''. In the first episode Dan mistakes Cora for a door-knocking Red Cross volunteer because of her shirt, and donates some money. It turns out she is his cousin's new girlfriend, isn't a volunteer, and designed and hand-made the shirt herself.

[[/folder]]

[[folder: Newspaper Comics ]]

* Cartoonist Ron Tandberg often depicted former [[AustralianPolitics Victorian Premier]] and [[AustralianRulesFootball Hawthorn Football Club]] president Jeff Kennett [[LiteralMetaphor literally doing this]] when he made a gaffe.

[[/folder]]

[[folder: Webcomics ]]

* ''Webcomic/AlienDice'': Lexx pulls this off [[http://aliendice.com/blog/2013/01/14/day-26-part-2-page-11-3/#comment here]].
* ''CodeNameHunter'': Gypsy stuffs [[UptoEleven both feet, up to her knees]] in when [[http://www.codenamehunter.com/archive/comic/2011/05/16 called to the commander's office]] by Queen Moraine. She's not in trouble. ''Yet''. One of the readers [[LampshadeHanging lampshaded]] this in the ShoutBox.
* ''Webcomic/{{Freefall}}'':
** Niomi is busy repairing the waste-water recycling plant. [[http://freefall.purrsia.com/ff600/fv00560.htm The toilets will work and you can get a drink.]]
** Sam Starfall tries to convince Florence not to trust Winston too quickly, [[http://freefall.purrsia.com/ff500/fv00490.htm only to accidentally confess to being everything but trustworthy]]
* ''Webcomic/TheWhiteboard'':
** [[http://www.the-whiteboard.com/autowb591.html In this strip]] Pirta and Swampy get into a brief discussion of his nickname. After Swampy asks about her name in an idiot moment for him, he comments that he can skip the appetizer, as he'll just chew on his own foot.
** In In [[http://www.the-whiteboard.com/autotwb1707.html this]] strip, a customer that's been hassling [[OnlySaneWoman Pirta]] for a date is asked if he'd be okay with the situation were their positions reversed, and she were trying to get him to cheat on his girlfriend. He accidentally lets slip that he'd be fine with cheating on his girlfriend Jenny for a date with Pirta. He winds up thrown bodily out of the store after being beat up by Pirta for his troubles.
* In ''TalesOfTheQuestor'', [[http://www.rhjunior.com/totq/00699.html when assuring a girl that people who take her for male are foolish, do not mention her hips.]]
* ''Webcomic/DanAndMabsFurryAdventures'':
** Aaryanna has the bad habit of invading the dreams her boyfriend Merlitz, but when she tried to convince Dan to embrace his [[HornyDevils Cubi's cultural heritage]], she commented that's nothing better for a cubi than simply invade other peoples' dreams... and she said that [[http://www.missmab.com/Comics/Vol_304.php within Merlitz's earshot.]]
** [[http://www.missmab.com/Comics/Vol_463.php The title says all]]...
** Abel, when he [[http://www.missmab.com/Comics/Abel_28.php has to explain his Cubi mark on his back]] (neither he or his mother were aware that he was a cubi at the time, but his theory of how it got there doesn't please his mother).
** Dan is a [[http://www.missmab.com/Comics/Vol_1064.php master of this trope]], and [[LampshadeHanging he is aware of this]].
** Lorenda does this [[UptoEleven epically]] [[http://www.missmab.com/Comics/Vol_1179.php here]].
* ''Webcomic/TheFoxSister'': Alex has a talent to say just the wrong things to Yun Hee.
* ''Dragon City'':
** Rachel makes a demeaning comment over the Ex-mayor, Donningan, saying that he was arrested for being ugly in the wrong place. [[http://dragoncity.thecomicseries.com/comics/515 Too bad that his grandaughter was within Rachel's earshot]].
** [[http://dragoncity.thecomicseries.com/comics/631 Sam would do the same mistake when he talked an explicit language to Rachel within Jonas' earshot]].
** Beatrix isn't a master in keep [[http://dragoncity.thecomicseries.com/comics/968 compromising secrets]] to herself.
* Done at least twice by Grey O'Shea in ''Webcomic/{{Terra}}'', though the best one is also the first. See [[http://www.terra-comic.com/wordpress/archives/437 page 130]] where he crossed it with RightBehindMe.
--> '''Simmons:''' ''(referring to Grey's rescue of Alex and Rick)'' C'mon, I saw that one of the officers was female, and a cute one at that--I know you, Grey.\\
'''Grey:''' Her?! Please, she's way too uptight. I don't have time for girls like that.\\
'''Simmons:''' What, you think you even stand a chance?\\
'''Grey:''' Give me a break. She may have an attitude, but if I wanted her, I could have her by the end of the night.\\
'''Alex:''' Hm, I'll take that bet.
* A RunningGag in ''Webcomic/SchlockMercenary'' is the multiple creative variations used to call someone (''usually'' Tagon, but he was by no means the only guilty party) out when they said something particularly embarrassing to or about another character while in earshot. It doesn't get mentioned as frequently in more recent strips as it did early on, but still pops up from time to time.
* ''Webcomic/{{Twokinds}}'': [[NoNameGiven "Red"]] has recently started running afoul of this trope. Winds up running into DiggingYourselfDeeper territory.
* A defining trait of Flux from ''[[{{Webcomic/Morphe}} morphE]]'' to the point that the comic introducing her was even named [[http://morphe.thewebcomic.com/comics/1802258/chapter-2-page-22-open-mouth/ Open Mouth]] to imply this very trope.

[[/folder]]

[[folder: Western Animation ]]

* ''TheFlintstones'': Fred literally did this on many occasions.
* Happens often in [[Disney/{{Aladdin}} Aladdin the animated series]] with the title character.
-->'''Iago:''' [[SarcasmMode Would you like some salt]] [[LampshadeHanging with your foot?]]

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