Question

Open a Can of Worms to cause trouble; to set unpleasant events in motion

Accepted Answer

If you mention my report card to my mother, you'll open a can of worms. A can of worms might be fine to open if you are by the banks of a river on a summer's day getting ready to fish. But you wouldn't want to open it anywhere else; the situation might cause a lot of trouble! In this expression, "worms" are difficult or delicate issues. A related idiom is "let sleeping dogs lie" (see page 111).

Idiom	Open a Can of Worms
Example	If you mention my report card to my mother, you'll open a can of worms.
Meaning	to cause trouble; to set unpleasant events in motion
Origin	A can of worms might be fine to open if you are by the banks of a river on a summer's day getting ready to fish. But you wouldn't want to open it anywhere else; the situation might cause a lot of trouble! In this expression, "worms" are difficult or delicate issues. A related idiom is "let sleeping dogs lie" (see page 111).

Open Worms Mention Report Card Mother Trouble Set