In my language there's a saying which literally translates to
Don't burn your house to smoke out a rat!
It advises us to use solutions that are appropriate to the magnitude of the problem.
Eliye pedichu illam chudaruthu! - in Malayalam/Indian.
What could be the English equivalent?
This idiom carries the same idea, but it is expressed as a description of what happens when the magnitude of the 'solution' far exceeds the needs of the problem:
This idiom has the reverse idea:
Instead of advocating restraint when a portion is bad and the rest is valuable, it advocates care when a portion is valuable and the rest is unwanted.
"Don't cut off your nose to spite your face."
It is not an exact match, but it is an interesting expression. Cutting off the nose to spite the face is used to:
describe a needlessly self-destructive over-reaction to a problem: "Don't cut off your nose to spite your face" is a warning against acting out of pique, or against pursuing revenge in a way that would damage oneself more than the object of one's anger.
...It was not uncommon in the Middle Ages for a person to cut the nose off of another for various reasons, including punishment from the state, or as an act of revenge. Cognitive scientist Steven Pinker notes that the phrase may have originated from this practice, as at this time "cutting off someone's nose was the prototypical act of spite."
The expression has since become a blanket term for (often unwise) self-destructive actions motivated purely by anger or desire for revenge. For example, if a man was angered by his wife, he might burn down their house to punish her; however, burning down her house would also mean burning down his, along with all of their possessions.
[Wikipedia]
In my neck of the woods, it is.
Don't kill flies with hand grenades
I believe the answers already posted hit the nail on the head but I feel this is appropriate for when someone has already used over the top methods or effort to solve an issue.
You were only supposed to blow the bloody doors off!
This comes from the film 'The Italian Job' and has been voted the favourite one liner from a film (in 2003), as such is probably quite well known. https://en.wikipedia.org/wiki/The_Italian_Job
It refers to a scene where a car's doors were meant to be blown off with a small explosion but instead the entirety of the vehicle is blown to pieces.
This I would consider a light hearted response provided the person you are talking with knows of this film. (It would also help to sport a Michael Caine accent if possible but not necesssary.)
The cure is worse than the disease
This is heard more often and refers to a similar situation. With both the burn-the-house and sledgehammer-as-nut-cracker "solutions" is that in the process, you undermine the need for a solution at all.
The "definition" for the sledgehammer phrase is summarized as "overkill", but that doesn't aptly express the problem. A hammer is not merely overkill, but will likely destroy the edible portion of the nut. Burning the house is not merely overkill to the problem of ridding it of a mouse, but will destroy your shelter.
An exact match in English is available!
Burn not your house to fright the mouse away
Prov. Do not do something drastic when it is not necessary
[The Free Dictionary]
If this sounds archaic, it can simply be re-phrased as
Don't burn your house to scare away a mouse
Usage
NewbieUser009: Man, I am sick of all the downvotes for my EL&U questions. I should probably delete my account.
EstablishedUser007: Now, that is not the solution, is it? Go through some popular questions, try to infer what is common among all the top voted questions and answers and try to ask compelling questions. Burn not your house to fright the mouse away.
I once heard this:
Don't use a cannon to kill a mosquito -- Confucius
Although this is a translation and not originally an English idiom, I believe it is relatively well known in the English language. So it might also be an option.
Another option is:
To use a sledgehammer to crack a nut :
- to use disproportionate force or expense to overcome a minor problem.
(The Phrase Finder)
The entire phenomena being described here - of doing something to solve your problem but ending up worse for it in the end - could be thought of as a pyrrhic victory
Someone who wins a Pyrrhic victory has been victorious in some way. However, the heavy toll negates any sense of achievement or profit.
Though the comparison isn't perfect - phyrric victories are more related to losing more than your foe, such that a wider 'war' is lost in the effort, whereas in your example, the personal 'war' is won, but the cost steeper than reasonable.
We used to say in our native language which means "if the nail grows too much, one should not cut the finger"
The one that I'm most familiar with is:
Like using a bazooka as a flyswatter.
For example, this was referenced in the title of one episode of the TV show The Good Wife.
But apparently there's all kind of permutations for this regarding large firearm (bazooka, cannon, shotgun, etc.) and small inoffensive creature (fly, mouse, sparrow, etc.).
More:
Don't use a steamroller to open a can of soup
for reference.. the opposite
There is no kill like overkill
or
If you're going to be a bear, be a grizzly -From Smokey and Bandit
A few phrases I've heard that kind of relate are...
I don't want to shotgun it
This phrase evokes the accuracy and precision of single projectile firearms as opposed to the spread nature of a shotguns pellets. Shotgunning something implies that you are causing collateral damage in an attempt to solve the problem.
A related example when you DO in fact want a massively disproportionate response to a small problem is that...
The virus had permeated my operating system folder, so I decided I should nuke the OS and reinstall.
Which of course states that something is so loathsome to you that you're willing to destroy everything in it's vicinity to get rid of it.
I think the answers have suggested many variants on this, but I would add the version I have heard:
Don't use an anti-aircraft gun to kill a bumblebee.
