Open a Can Of Worms


If someone says, “you have opened a can of worms,” it means you said or did something that caused a situation to become more troublesome or complicated.

Example: One of Jessica’s coworkers smells bad. She wants to talk to him about this ongoing problem, but she’s worried that doing so might open a can of worms; so she spoke to HR instead.

1. Stir the hornet’s nest

An open cat of worms with dirt.
This is a can. What’s inside? Worms.

The Origin Of ‘Open a Can Of Worms’

The origin of this phrase may come from fishing. The reason is because people often buy and open cans of worms to use as bait during this activity.

Indeed, bait is a big part of fishing; it helps to lure the fish in. Besides worms, there are other types of bait that are used. For example, ‘spinner-bait’ is made up of small pieces of metal that spin around when it’s reeled in. This bait causes vibrations in the water similar to that of smaller fish, which in turn might fool larger fish into taking a bite.

What about worms? Fishing stores sell cans of worms, so fishermen looking for some simple bait might buy one and open it later. Unsurprisingly, inside these cans are numerous worms. While closed, the worms are contained and under control. However, once the can is opened, the worms start wiggling around and things may get a little messy. The point is that worms become more troublesome to deal with after the can is opened. This is comparable to situations that seem manageable at first, but later something happens that makes the situation more troublesome; it’s like someone opened a can of worms.

Tip: Want to find more sayings like this? Here is a list of phrases starting with “O” that you can browse through. Find common phrases on there and more!

Anyway, how old is this phrase? The earliest I have seen this idiom in print is in The Edwardsville Intelligencer newspaper, November 1951:

“The question of command for Middle East defense against Soviet Aggression is still regarded as ‘a can of worms’ at General Elsenhower’s SHAPE headquarters here.”

Example Sentences

  • My roommates are messy, so I tried to politely tell them to start cleaning up after themselves. However, this opened a can of worms because now they are arguing with each other.

Similar Example:

  • Someone was rude to me at the store, but not wanting to stir the hornets nest, I let it go.

Tip: If you want to find more popular sayings, use the menu at the top.