open a can of worms
Meaning
To start dealing with a complex issue that creates many new problems or complications.
Origin
From the literal idea that opening a container of live worms (often sold as fishing bait) makes them wriggle out and become hard to control; figuratively, it means unleashing complications.
Notes
Suggests that addressing a topic will unleash messy, unforeseen complications. Often used as a warning (“don’t…”) or to describe unintended consequences.
Examples
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If we question the budget this late, we might open a can of worms.
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Asking about his previous job opened a can of worms I didn’t expect.
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The investigation could open a can of worms and expose problems across the whole department.
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Don’t mention the inheritance tonight—you’ll open a can of worms at dinner.
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Updating the old software seemed simple, but it opened a can of worms with compatibility issues.
Grammar & Usage Notes
Fixed phrase: most commonly “open a can of worms,” but can inflect (“opened/opening a can of worms”). Often used with objects like “by asking that question, you’ll open a can of worms.” Article is typically “a.”
Synonyms
- stir up trouble
- raise a hornet's nest
- stir the pot
- poke the bear
Antonyms
- resolve the issue
- tie up loose ends
- settle the matter