someone tries to fix a tiny mistake at work, but instead, the whole project turns into a disaster. Or a friend brings up an old argument during dinner, and suddenly everyone’s upset again. That, my friends, is what we call a can of worms. In this post, we’ll unpack its meaning, trace its curious origin, and look at how to use it naturally in both serious and funny situations.
Meaning of A Can of Worms
The idiom “a can of worms” means a situation that becomes complicated or problematic once it’s started or discussed. It suggests that something that looked simple on the surface actually hides a tangled mess underneath.
Common uses:
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When someone accidentally creates more problems while trying to solve one.
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When a conversation topic leads to uncomfortable or endless debate.
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When a small action triggers unexpected consequences.
In short:
👉 Opening a can of worms = starting something that leads to a mess of trouble or confusion.
Origin of A Can of Worms
The expression comes from the literal act of opening a can of fishing worms—a real product sold to anglers in the early 1900s. Once opened, the worms wriggled out, making it nearly impossible to put them all back in.
This messy image perfectly captured what happens when a person brings up a difficult issue or begins a complex task. The metaphorical use of “a can of worms” first appeared in American English in the 1950s, and it has stuck ever since as a colorful way to describe situations that spiral out of control.
Examples in Sentences
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Starting that audit opened a real can of worms—now we’re finding mistakes everywhere.
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Bringing up her ex during the party was a total can of worms.
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Revising the company policy sounded easy, but it turned into a can of worms when everyone wanted a say.
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If we investigate that issue, we might open a can of worms we can’t close.
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In the meeting, he realized too late that his question had opened a can of worms about management decisions.
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Talking about politics at family gatherings? Always a can of worms.
Similar Idioms or Phrases
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Pandora’s box – Refers to an action that releases many unforeseen problems or troubles.
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The tip of the iceberg – When what’s visible is only a small part of a much bigger, more complicated issue.
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Skeletons in the closet – Hidden secrets that can cause problems if revealed.
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Opening a Pandora’s jar – A classical variation with the same cautionary meaning.
PERSONAL INSIGHT
I like using “a can of worms” when I’m describing a problem that grows bigger the more you poke at it—like trying to “just clean your desk” and ending up reorganizing your whole life. It’s such a vivid, slightly gross image that people instantly get what you mean. It’s one of those idioms that makes English both practical and playfully visual.
CONCLUSION
So, “a can of worms” isn’t about fishing anymore—it’s about situations that spin out of control once opened. Whether you’re discussing work issues, family drama, or political debates, this idiom captures the chaos perfectly.
Do you use “a can of worms” in your everyday conversations? Share your favorite examples in the comments below!