What does It Mean to "Open a can of Worms"?

Michael Pollick
Michael Pollick

Metaphorically speaking, to open a can of worms means to inadvertently create numerous new problems while trying to solve one. Experts disagree on the origin of the phrase, but it is generally believed to be a Canadian or American metaphor coined sometime in the 1950s. Bait stores routinely sold cans of worms and other popular live baits to fishermen, who often discovered how easy it was to open them and how difficult it was to close them. Once the worms discovered an opportunity to escape, it became nearly impossible to keep them contained.

Fishermen routinely find that, once a can of worms has been opened, it's hard to get the creatures back in.
Fishermen routinely find that, once a can of worms has been opened, it's hard to get the creatures back in.

Some experts say the metaphor is a modern extension of Pandora's Box. In the original story, a mortal was warned not to open a box belonging to Pandora. When curiosity got the best of this mortal, she opened the box and inadvertently released numerous plagues on the world. According to legend, the only thing remaining in Pandora's box was a creature called Hope. In this same sense, to open a can of worms means to release a host of often irrevocable problems or complications. As long as the "can" remained sealed, there would be no harm.

It is rarely a good thing to open a can of worms, although the damage control process could prove to be cathartic. An accountant looking for answers to a tax problem could discover evidence of financial wrongdoing by his client, for example. The exposure of that one secret could set off a chain of events with even more dire consequences. Once the accountant decided to open the can, however inadvertently, the worms themselves triggered an entirely new set of problems. By exposing the truth to the light, however, the situation could now be handled honestly.

Sometimes the decision to open a can of worms does not work out so well. History is full of events in which the investigation of one problem has led to the exposure of dozens of other problems lurking beneath the surface. Investigations, such as the Washington Post inquiry into a break-in at the Watergate office complex in 1972, often expose scandals much bigger than the original story. There is often no elegant or efficient way to reseal the ugly truth once someone decides to reveal it.

Michael Pollick
Michael Pollick

A regular wiseGEEK contributor, Michael enjoys doing research in order to satisfy his wide-ranging curiosity about a variety of arcane topics. Before becoming a professional writer, Michael worked as an English tutor, poet, voice-over artist, and DJ.

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Discussion Comments


SauteePan- We must have had the same mother, because my mother always used to say that. There is another saying that says, “No ese igual llamado el diablo, que verlo llegaded”

This translates that it is not the same to call the devil then see him arrive. This refers to people who take extraordinary risks.

The aspect of calling the devil refers to taking chances that you shouldn’t take, and when the devil arriving means that as a result of your risk taking you are now dealing with a horrible situation, which would be when the devil arrives.


Moldova- I know that there are well-known Spanish idioms like, “De la justicia de Dios no se escapa nadie”.

This means that no one escapes God’s justice which means that sooner or later you will pay for what you did which is a reference to karma.


Oasis11- That is too funny. I always use idioms sayings like, “Open a can of worms” idiom, or let the cat out of the bag when someone discloses a secret.

I never thought about how confusing idioms can be for foreigners. When they hear, “Par for the course”, they don’t understand that it means that is what is expected. It really has nothing to do with a golf game.


Idioms phrases must be really confusing to someone learning English. For example, when you say that you “Beat a dead horse” you are really saying that you have done all that you can do regarding a situation and there is nothing else to do.

But someone learning the English language for the first time might actually think that you are hitting a horse.

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