"When you hear hoofbeats behind you, don't expect to see a zebra"

-- Dr. Theodore Woodward

In the genre of medical drama, Occams Razor is disregarded and writers usually go for the most unusual type of diagnosis available. This differs greatly from real life where a cough is usually just a cough.

The etymology of this trope name comes from the quote at the top of the page, medical students are all told to "think horses, not zebras".

However, this trope is justified in the sense that a mere stomach flu would make for some real boring TV.

One of the most notorious offenders of this trope is House MD, yet nearly every medical mystery show has at least one far fetched plot.