Idiom: open a can of worms

Cartoon man looks shocked at tangled worms from an opened can, illustrating the idiom 'open a can of worms.' Caption: Joe's question at the meeting opened a can of worms.

Open a can of worms (idiom)

When is the last time you 'opened a can of worms.'   

(open / open up) a can of worms:  a situation or issue that becomes even more complicated as you try to deal with it or solve the problem.


Fishermen often attach a live worm to their fishing hooks as bait to catch a fish. They may carry the worms in a can (like in the picture above), when they open it a bunch of tangled worms will crawl out. By trying to help yourself catch a fish you have created a messy problem or situation.

Over time, the phrase has changed and developed to describe any situation that reveals more problems once you start looking into it. It suggests that sometimes it's better to leave certain things alone rather than risk making them more complicated.

Sentence examples

— When Sarah decided to look at her boyfriend's iPhone she opened a can of worms.

— When I discovered white powder in my daughter's bathroom I thought I'd found a can of worms but fortunately it was only translucent face powder.

— I never reported my supervisor's sexual comments because I thought it would just open up a can of worms and my situation would become even worse.

— Commenting on my wife's appearance always opens a can of worms so I never say anything anymore.

— The investigation of the police chief opened a can of worms at the police department.

— Our new spokesman opened a can of worms when he got arrested for drunk driving—for starters, we work with handicapped children so it's not good for our image and now he is not able to travel abroad for the next three months.

— Giving my secretary a small raise opened a can of worms at the firm because everyone found out about it and now they want the same salary increase.

— The investigation of donations made to the winning candidate during the election has really opened a can of worms.

— I'd never have imagined that my daughter's selling cookies at the park would open a can of worms but now we are in trouble with three different government departments.

— I feel like bringing my girlfriend home for the holidays might open a can of worms but she really wants to go.

— The audit opened a can of worms revealing corruption, bribery and nepotism at the nonprofit organization.

— Whenever my roommate talks about her family's history, she opens a can of worms.

— Why are you always opening a can of worms in the middle of our team meetings?

— They've opened a can of worms by deciding to renovate the entire house.

— If you bring up the topic of politics at the dinner, you're going to open a can of worms.

— My uncle tried repairing the plumbing himself but he only opened a can of worms. Now he's got to pay $2,500 to a plumber to fix the problem.

— Don't you think asking your date about his past relationships at this point would open a can of worms?

— Changing the company's software opened up a can of worms, with many unexpected issues arising.

— Our new Marketing Director thought reorganizing the team would be straightforward, but it was like opening a can of worms.

— Proposing a new policy at the conference opened up a can of worms and lead to heated debates.


  • stir up a hornet's nest
  • a pandora's box
  • kick the hornet's nest
  • rattle someone's cage


  • smooth sailing
  • clear the air

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