Do Mothballs Keep Mice Away?

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Mice can be, to put it simply, a menace. One tiny mouse can wreak more havoc than you could possibly imagine before you even detect its presence in your home. And seeing as rodents seem to be getting smarter and developing different methods to evade the traps set to kill them or to at least keep them away (they’re actually just afraid of new things), it is no surprise that there have been many methods devised to facilitate their extermination.

One such method is the use of a high concentration of mothballs.

With either paradichlorobenzene or naphthalene as its active ingredient, a mothball is a white ball-shaped pesticide sometimes used to keep pests away.


Faizal Ramli/

The purpose of this article is to provide answers to frequently asked questions about the use of mothballs to keep mice away, including do mothballs repel mice in the first place and what mothballs do to mice.

It is important at this point to state that the chemicals that mothballs contain are highly-toxic fumigants that are volatile when exposed to open air.

What this means is that mothballs in open spaces react with the air to create fumes that may deter rodents and other pests from that vicinity.

However, for mothballs to do more than just cause discomfort to mice and to actually serve as a permanent solution to keep them away, the fumigant concentration must be high.

When applied in a high concentration, the fumigant in mothballs damages the indoor air quality. While this is toxic to mice and rats, it is toxic to humans and pets as well.

Mothballs are a pesticide. Their purpose is to kill moths and their eggs and larvae. As a pesticide, they are regulated by the Environmental Protection Agency (EPA) and any use not specified on the label is illegal.

They are only to be used inside airtight containers to get rid of clothes moths. They should not be scattered out in the open where they will release toxic vapors that are dangerous for people and other animals as well as the environment.

In addition, mothballs may look like candy to children or treats to a pet. But if ingested, the poisons in mothballs can cause vomiting, trouble breathing, seizures, kidney and liver damage, and can even be fatal.

How do mothballs get rid of mice?

Mothballs are not an effective pest repellent.

The idea is that when the fumigants in mothballs react with the air, they give off certain fumes that are irritating to mice and rats. As such, rodents are expected to keep away from environments where mothball fumes are present.

But, again, the intended use of mothballs is to keep moths and their larvae away from clothing.

The advantages of using mothballs to get rid of mice

  • Availability: Mothballs can be easily purchased from online stores or department stores near you. However, beware of illegally-sold mothballs. Their ingredients are not regulated by the EPA and may be more dangerous than legally-sold mothballs.
  • Cost: Mothballs are inexpensive.
  • Ease of use: They’re easy to set out. However, they are very dangerous, which outweighs their ease of use.

There are, however, some disadvantages that you should consider.

The disadvantages of using mothballs to get rid of mice

  • Toxicity: As stated earlier, mothballs react with the air and release fumes that are toxic to people and could cause illness. In pets and small children, their effects can be fatal. The harm that could come from exposure to a high concentration of the toxic chemicals found in mothballs is one major setback when it comes to using this pesticide. One way to avoid this setback is to leave your house if you set out fresh mothballs in your home.
  • Harmful to pets and children: Mothballs are shaped like tiny white balls which is tempting for toddlers who are keen on putting whatever they touch in their mouths. Additionally, your pets could chew on any mothballs they find as well or could be affected negatively by their toxic fumes. You can find natural alternatives here.
  • Ineffective outdoors: Using mothballs outdoors does not work very well as weather conditions such as rainfall can easily dissolve them.
  • Potentially ineffective indoors: There is anecdotal evidence that mothballs work and just as much that they don’t. It’s better to keep yourself and your family safe rather than use a dangerous method that may not work at all. Stick to the tried and true methods of sanitation, exclusion, and baiting.

We do not recommend using mothballs to repel mice or any other pest.

Additional Resources


Debbie Darland

what do you do if mothballs are put in your home and so stong you cant breath


    Everyone should keep out of the house while the toxic fumes are still present. If you can feel the smell, it’s obvious you should keep away for some while until they have completely dispersed.


My friend in Italy gets an infestation of mice in her car in winter. I suggested placing Mothballs in the car but would this be dangerous to her and her dog? Would she have to remove them each time she drives and replace them on return?


    Using mothballs in your car definitely isn’t the best idea. Mothballs contain substances that react with the air and release toxic fumes which can be especially dangerous when used in small spaces and around pets. I’d recommend you check out our article on keeping rodents out of your car to find out what your friend can do to keep mice out of her car in the winter.

Lori G Main

How long does it take for the mothballs smell/odor to go away? Had a mouse die inside my shower wall so I put about 10 mothballs down inside the 2 walls. I was able to drop them through a small space at top of drywall. Then I closed bathroom door for 3 days and opened the exterior window.

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