A character sneezes once, says they feel a bit funny, or coughs once—and everyone else thinks that character is sick. The character does not show any illness signs except that one sneeze or cough (which in reality is not a biggie), but nevertheless the other characters put him/her in bed, or they have to miss something fun or important or both. Often at the end of the episode another character "catches" the false illness by sneezing once. And if there is an actual Sick Episode, at the end this trope often ensues in a second character, especially with coughing or sneezing. Perfect Health (where the characters never sneeze, cough etc unless they are sick) is a similar trope but in this one, the character shows no other symptoms over the course of the episode and therefore most likely is not sick.
All examples of this trope are when a character is assumed sick by one little "glitch", but doesn't show any other symptoms. Any instances where they do show any other symptoms over the course of the episode (fever, persistent unidentified cough, severe headache, wheezing etc) are Not an Example.
Compare Logical Fallacies, Perfect Health, and O.O.C. Is Serious Business (if that glitch was somehow out of character). Contrast Deadly Nosebleed, Incurable Cough of Death (when it seems like this trope but turns out to actually be an illness) and Definitely Just a Cold. Also compare Victorian Novel Disease (except the victims of this often are genuinely sick) and Hypochondria (when someone does one of these on themselves).
- One episode of Lost Universe has the crew of the Swordbreaker sent to restore order to a medical school with insanely overcompetitive students trying to outdo or sabotage each other. At one point Milly sneezes once, and promptly gets swarmed by students trying to diagnose and treat her condition. Milly ends up totally covered in bandages, which would suggest that the students weren't ready for finals at all, as illnesses generally don't require bandaging.
- An in-universe example in the Shirley Temple version of The Poor Little Rich Girl (a Lighter and Softer In Name Only remake of the silent original): besides being a Lonely Rich Kid whose father is too busy to spend much time with her, Shirley's character has to deal with a fussy nanny who sends her to bed just because she sneezes three times.
- Clarissa Explains It All:
- In "Sick Days," Clarissa just sneezes once, then opens the window because she feels hot, and right away her mother insists on taking her temperature and finds that she has a fever. Despite the rest of the episode being a Sick Episode, occasional sneezes are the only real symptoms she shows.
- Near the end of "The Flu," Clarissa realizes just from sneezing twice that she's caught the flu from her parents. Averted with the parents at the beginning, though, who can't stop sneezing and are exhausted, shivering and feverish.
- My Left Nut: Mick becomes convinced he has testicular cancer after the first few exams and thinks his days are numbered, which causes a great negative impact on his social life.
- Sesame Street: Madlenka is thought to have a cold but in reality she only sneezed once. Also Telly's joke "Knock Knock", "Who's There?'' "Atch" "Atch who?" "Sorry you're sneezing. Have you got a cold?"
- Star Trek: The Next Generation: When Data is practicing sneezing, Wesley Crusher asks if he has a cold. Which is strange as Data is an android and colds do not exist in the 24th Century.
- Little Princess: Princess catches a cold and at the end she thinks the adults are sick as they all sneeze once.
- Rugrats: Didi Pickles thinks all sneezing, being a bit moody, or shivering is a sign of illness. So do Drew and Angelica Pickles. Also, Chas often worries something is wrong with Chuckie or Kimi if they seem a bit moody/odd.
- Harry and His Bucket Full of Dinosaurs: At the end of a Sick Episode appropriately titled Achoo, Steggy (the shyest of the bunch) says he is finally sick because he sneezed once.
- Hanas Helpline: Maggie sneezes, Hana thinks she has a cold, then Hana sneezes and believes she has caught Maggie's "cold".
- In the My Friends Tigger & Pooh episode "Darby, Solo Sleuth" it is confirmed that Roo, Tigger, Pooh, Beaver and Eeyore really do have colds but Rabbit, Darby and Buster only sneeze once and are thought by Darby to have colds.
- In the What's New, Scooby-Doo? episode "There's No Creature Like Snow Creature", Velma sneezes several times but does not seem sick and Daphne deems her "too sick to think" and thinks she should rest.
- At the end of the How To Catch A Cold Disney video, the tiny man known as Common Sense sneezes and says "Oh no". Which is ironic as believing sneezing once means you are sick (in addition to earlier on, saying that being moody makes you likely to catch cold and you'll Catch Your Death of Cold, means he partly lacks in "common sense".
- The Hive, when Buzz Bee wakes up he sneezes and Mummy Bee says "oh dear".
- Arthur Sick Episode "Is There A Doctor in the House?" The parents are sick. Then at the end Arthur sneezes and D.W. says "Uh oh", then it ends.
- Curious George episode "Monkey Fever". At the end of this Sick Episode, George sneezes and the man with the yellow hat says he's caught his cold.
- Postman Pat in an episode where Julian is Playing Sick, Jess fell down a hole and broke his leg, then when Postman Pat coughs once and is a bit tired, the vet says he is sick.
- The third 38 Parrots short is about the Python being mistaken for sick.
- Aladdin: The Series: at the end of the episode "Sneeze the Day," after finishing a Find the Cure! quest and curing the Genie's cold, Aladdin sniffs once, then sneezes once, and the Genie instantly decides he has a cold and starts pampering him.
- The Loud House: In "One Flu Over the Loud House", Lincoln suspects Lucy to be infected twice because she looks pale, even though she always does.